* tests/core/ltl2tgba2.test, tests/core/ltldo.test,
tests/core/ltlfilt.test, tests/core/neverclaimread.test,
tests/core/parseaut.test, tests/sanity/bin.test: Here.

* spot/tl/ltlf.cc: Here.
* tests/core/ltlfilt.test: Adjust test case.

This was prompted by reports by Andrew Wells and Yong Li.

* NEWS, doc/tl/tl.tex: Document the changes.
* THANKS: Add Andrew.
* bin/ltlfilt.cc: Match --ltl before --from-ltlf if needed.
* spot/parsetl/parsedecl.hh, spot/parsetl/parsetl.yy,
spot/parsetl/scantl.ll: Parse X[!].
* spot/tl/formula.cc, spot/tl/formula.hh: Declare the new operator.
* spot/tl/ltlf.cc: Adjust to handle op::X and op::strong_X correctly.
* spot/tl/dot.cc, spot/tl/mark.cc, spot/tl/mutation.cc,
spot/tl/print.cc, spot/tl/simplify.cc, spot/tl/snf.cc,
spot/tl/unabbrev.cc, spot/twa/formula2bdd.cc,
spot/twaalgos/ltl2taa.cc, spot/twaalgos/ltl2tgba_fm.cc,
tests/core/ltlgrind.test, tests/core/rand.test,
tests/core/sugar.test, tests/python/randltl.ipynb: Adjust.
* tests/core/ltlfilt.test, tests/core/sugar.test,
tests/core/utf8.test: More tests.

* spot/gen/formulas.cc, spot/gen/formulas.hh, bin/genltl.cc: Implement
this.
* NEWS, bin/man/genltl.x, doc/spot.bib: Add documentation.
* tests/core/genltl.test, tests/core/ltlfilt.test: Add some tests.

The first issue was reported by Victor Khomenko.

* spot/tl/formula.cc: Introduce a single-argument
version of sugar_delay().
* spot/parsetl/parsetl.yy: Use it.
* doc/tl/tl.tex, spot/tl/formula.hh: Adjust doc.
* tests/core/ltlfilt.test, tests/core/sugar.test: More tests.

Since b[+] and [*0] are siSERE, b* is siSERE as well.
Suggested by Victor Khomenko.

* spot/tl/formula.cc: Implement that for Star and also
in the concatenation rule.
* tests/core/kind.test, tests/core/ltlfilt.test: Adjust.

Since b[+] and [*0] are siSERE, b* is siSERE as well.
Suggested by Victor Khomenko.

* spot/tl/formula.cc: Implement that for Star and also
in the concatenation rule.
* tests/core/kind.test, tests/core/ltlfilt.test: Adjust.

Reported by Victor Khomenko.

* spot/tl/formula.cc: Rewrite the siPSL detection for ";".
* tests/core/ltlfilt.test: Add more tests.
* tests/core/kind.test: Adjust.
* NEWS: Mention the bug.

Reported by Victor Khomenko.

* spot/tl/formula.cc: Rewrite the siPSL detection for ";".
* tests/core/ltlfilt.test: Add more tests.
* tests/core/kind.test: Adjust.
* NEWS: Mention the bug.

* spot/twaalgos/strength.cc, spot/twaalgos/strength.hh,
spot/tl/hierarchy.cc, spot/tl/hierarchy.hh: Here.
* bin/ltlfilt.cc (--liveness): New filter.
* NEWS: Mention those.
* tests/core/ltlfilt.test, tests/python/ltlsimple.py: Add test cases.

* bin/ltlfilt.cc: Add the option.
* tests/core/ltlfilt.test: Use it.
* NEWS: Mention it.

* bin/ltlfilt.cc: Add the option.
* tests/core/ltlfilt.test: Use it.
* NEWS: Mention it.

* tests/core/ltlfilt.test: here

* tests/core/ltlfilt.test: Add test cases.

Our use of
  ltl2tgba=ltl2tgba
  autfilt=autfilt
  ...
all over the test cases comes from the time where those tools were not
in PATH and we actually had something like
  ltl2tgba=../../bin/ltl2tgba
  autfilt=../../bin/autfilt

But today that is useless, and we prefer to write ltl2tgba rather than
$ltl2tgba, so let's remove this old cruft.

* tests/core/basimul.test, tests/core/det.test, tests/core/lbt.test,
tests/core/lenient.test, tests/core/ltl2dstar.test,
tests/core/ltl2dstar2.test, tests/core/ltl2dstar3.test,
tests/core/ltl2dstar4.test, tests/core/ltlcross2.test,
tests/core/ltlcross3.test, tests/core/ltlcross4.test,
tests/core/ltlcrossce2.test, tests/core/ltldo.test,
tests/core/ltlfilt.test, tests/core/optba.test,
tests/core/prodor.test, tests/core/rand.test,
tests/core/randomize.test, tests/core/remfin.test,
tests/core/satmin.test, tests/core/sbacc.test,
tests/core/strength.test, tests/core/stutter-ltl.test,
tests/core/stutter-tgba.test, tests/core/unabbrevwm.test,
tests/core/unambig.test: Get rid of all tool=tool assignments.

Reported by Shufang Zhu.

* spot/tl/ltlf.cc, spot/tl/ltlf.hh: Fix the transltion
and update the comments.
* tests/core/ltlfilt.test: Adjust test cases.
* NEWS: Mention the fix.
* THANKS: Add Shufang Zhu.

Reported by Shufang Zhu.

* spot/tl/ltlf.cc, spot/tl/ltlf.hh: Fix the transltion
and update the comments.
* tests/core/ltlfilt.test: Adjust test cases.
* NEWS: Mention the fix.
* THANKS: Add Shufang Zhu.

Fixes #187.

* spot/tl/ltlf.cc, spot/tl/ltlf.hh: New files.
* spot/tl/Makefile.am: Add them.
* bin/ltlfilt.cc: Add a new option.
* bin/man/ltlfilt.x: Add bibliographic reference.
* tests/core/ltlfilt.test: Add more tests.
* tests/python/ltlf.py: New file.
* tests/Makefile.am: Add it.
* python/spot/impl.i: Python bindings.
* NEWS: Mention it.

Part of #91.

* spot/misc/formater.cc, spot/misc/formater.hh: Here.
* bin/common_output.cc: Adjust automatic output format.
* doc/org/csv.org: Adjust.
* tests/core/lbt.test, tests/core/ltlfilt.test: More tests.
* NEWS: Mention the changes.

Fixes #181.

* bin/common_range.cc: Here.
* tests/core/ltlfilt.test: Add test case.

Fixes #131.

* bin/ltlfilt.cc: Implement the option.
* tests/core/ltlfilt.test: Test it.
* NEWS: Mention it.

* tests/: Rename as...
* tests/core/: ... this.
* python/tests/: Rename as...
* tests/python/: ... this.
* python/tests/run.in: Move as...
* tests/run.in: This, and adjust.
* tests/Makefile.am: Adjust to run both core and python tests.
* configure.ac, README, debian/python3-spot.examples, debian/rules,
doc/org/tut.org, python/Makefile.am, spot/ltsmin/Makefile.am,
spot/ltsmin/kripke.test, spot/sanity/ipynb.test: Adjust.

* spot/bin/: Move...
* bin/: ... here.
* spot/tests/: Move...
* tests/: ... here.
* Makefile.am, README, bench/stutter/Makefile.am,
bench/stutter/stutter_invariance_formulas.cc, doc/Makefile.am,
configure.ac, debian/rules, spot/Makefile.am, spot/ltsmin/Makefile.am,
spot/ltsmin/kripke.test, spot/sanity/style.test, python/tests/run.in:
Adjust.

* NEWS: Mention the change.
* src/: Rename as ...
* spot/: ... this, adjust all headers to include <spot/...> instead of
"...", and adjust all Makefile.am to search headers from the top-level
directory.
* HACKING: Add conventions about #include.
* spot/sanity/style.test: Add a few more grep to catch cases
that do not follow these conventions.
* .gitignore, Makefile.am, README, bench/stutter/Makefile.am,
bench/stutter/stutter_invariance_formulas.cc,
bench/stutter/stutter_invariance_randomgraph.cc, configure.ac,
debian/rules, doc/Doxyfile.in, doc/Makefile.am,
doc/org/.dir-locals.el.in, doc/org/g++wrap.in, doc/org/init.el.in,
doc/org/tut01.org, doc/org/tut02.org, doc/org/tut03.org,
doc/org/tut10.org, doc/org/tut20.org, doc/org/tut21.org,
doc/org/tut22.org, doc/org/tut30.org, iface/ltsmin/Makefile.am,
iface/ltsmin/kripke.test, iface/ltsmin/ltsmin.cc,
iface/ltsmin/ltsmin.hh, iface/ltsmin/modelcheck.cc,
wrap/python/Makefile.am, wrap/python/ajax/spotcgi.in,
wrap/python/spot_impl.i, wrap/python/tests/ltl2tgba.py,
wrap/python/tests/randgen.py, wrap/python/tests/run.in: Adjust.

Flatten the formula ltl::formula hiearchy into a single ltl::vnode that
has an enumerator to distinguish the types of node, and a common
interface to access children, update reference counts, etc.  The
ltl::formula class is now a thin wrapper around an ltl::vnode pointer to
keep track of reference counts automatically.  Visitor are not used
anymore; we now have map() and traversor() methods that are more
concise.

This basically fixes #43, but should be followed by some fine tuning
that should now be localized to the formula.hh and formula.cc files.

Some statistics about this patch.  I started working on it on Sep 9, had
a first compiling version two weeks later on Sep 22, and it then took 5
days to fixes the ~70 distincts bugs that were introduced during the
conversion.  About 13200 lines were modified, and one third of those
were removed.

* src/ltlast/formula.cc, src/ltlast/formula.hh: Complete rewrite,
including what was in separate nearby files.
* src/ltlast/allnodes.hh, src/ltlast/atomic_prop.cc,
src/ltlast/atomic_prop.hh, src/ltlast/binop.cc, src/ltlast/binop.hh,
src/ltlast/bunop.cc, src/ltlast/bunop.hh, src/ltlast/constant.cc,
src/ltlast/constant.hh, src/ltlast/multop.cc, src/ltlast/multop.hh,
src/ltlast/unop.cc, src/ltlast/unop.hh, src/ltlvisit/dump.cc,
src/ltlvisit/dump.hh, src/ltlast/predecl.hh: Delete these files.  Their
feature have been merged in formula.hh and formula.cc.
* src/ltlast/visitor.hh, src/ltlvisit/clone.cc, src/ltlvisit/clone.hh,
src/ltlvisit/dump.hh, src/ltlvisit/postfix.cc, src/ltlvisit/postfix.hh:
Delete these files, as we do not use visitors anymore.
* bench/stutter/stutter_invariance_formulas.cc,
bench/stutter/stutter_invariance_randomgraph.cc, doc/org/tut01.org,
doc/org/tut02.org, doc/org/tut10.org, doc/org/tut22.org,
iface/ltsmin/ltsmin.cc, iface/ltsmin/ltsmin.hh,
iface/ltsmin/modelcheck.cc, src/bin/autfilt.cc,
src/bin/common_aoutput.cc, src/bin/common_aoutput.hh,
src/bin/common_finput.cc, src/bin/common_finput.hh,
src/bin/common_output.cc, src/bin/common_output.hh,
src/bin/common_trans.cc, src/bin/common_trans.hh, src/bin/dstar2tgba.cc,
src/bin/genltl.cc, src/bin/ltl2tgba.cc, src/bin/ltl2tgta.cc,
src/bin/ltlcross.cc, src/bin/ltldo.cc, src/bin/ltlfilt.cc,
src/bin/ltlgrind.cc, src/bin/randaut.cc, src/bin/randltl.cc,
src/kripke/kripkeexplicit.cc, src/kripke/kripkeexplicit.hh,
src/kripkeparse/kripkeparse.yy, src/ltlast/Makefile.am,
src/ltlenv/declenv.cc, src/ltlenv/declenv.hh, src/ltlenv/defaultenv.cc,
src/ltlenv/defaultenv.hh, src/ltlenv/environment.hh,
src/ltlparse/ltlparse.yy, src/ltlparse/public.hh,
src/ltlvisit/Makefile.am, src/ltlvisit/apcollect.cc,
src/ltlvisit/apcollect.hh, src/ltlvisit/contain.cc,
src/ltlvisit/contain.hh, src/ltlvisit/dot.cc, src/ltlvisit/dot.hh,
src/ltlvisit/exclusive.cc, src/ltlvisit/exclusive.hh,
src/ltlvisit/length.cc, src/ltlvisit/length.hh, src/ltlvisit/mark.cc,
src/ltlvisit/mark.hh, src/ltlvisit/mutation.cc,
src/ltlvisit/mutation.hh, src/ltlvisit/nenoform.cc,
src/ltlvisit/nenoform.hh, src/ltlvisit/print.cc, src/ltlvisit/print.hh,
src/ltlvisit/randomltl.cc, src/ltlvisit/randomltl.hh,
src/ltlvisit/relabel.cc, src/ltlvisit/relabel.hh,
src/ltlvisit/remove_x.cc, src/ltlvisit/remove_x.hh,
src/ltlvisit/simpfg.cc, src/ltlvisit/simpfg.hh,
src/ltlvisit/simplify.cc, src/ltlvisit/simplify.hh, src/ltlvisit/snf.cc,
src/ltlvisit/snf.hh, src/ltlvisit/unabbrev.cc, src/ltlvisit/unabbrev.hh,
src/parseaut/parseaut.yy, src/ta/taexplicit.cc, src/ta/tgtaexplicit.cc,
src/taalgos/minimize.cc, src/taalgos/tgba2ta.cc, src/tests/bare.test,
src/tests/checkpsl.cc, src/tests/checkta.cc,
src/tests/complementation.cc, src/tests/consterm.cc,
src/tests/emptchk.cc, src/tests/equalsf.cc, src/tests/ikwiad.cc,
src/tests/isop.test, src/tests/kind.cc, src/tests/length.cc,
src/tests/ltldo.test, src/tests/ltlfilt.test, src/tests/ltlgrind.test,
src/tests/ltlprod.cc, src/tests/ltlrel.cc,
src/tests/parse_print_test.cc, src/tests/parseaut.test,
src/tests/parseerr.test, src/tests/randtgba.cc, src/tests/readltl.cc,
src/tests/reduc.cc, src/tests/syntimpl.cc, src/tests/taatgba.cc,
src/tests/tostring.cc, src/tests/twagraph.cc, src/tests/utf8.test,
src/twa/acc.cc, src/twa/bdddict.cc, src/twa/bdddict.hh,
src/twa/bddprint.cc, src/twa/formula2bdd.cc, src/twa/formula2bdd.hh,
src/twa/taatgba.cc, src/twa/taatgba.hh, src/twa/twa.cc, src/twa/twa.hh
src/twa/twagraph.cc, src/twa/twagraph.hh, src/twa/twasafracomplement.cc,
src/twaalgos/compsusp.cc, src/twaalgos/compsusp.hh,
src/twaalgos/dtgbasat.cc, src/twaalgos/hoa.cc, src/twaalgos/lbtt.cc,
src/twaalgos/ltl2taa.cc, src/twaalgos/ltl2taa.hh,
src/twaalgos/ltl2tgba_fm.cc, src/twaalgos/ltl2tgba_fm.hh,
src/twaalgos/minimize.cc, src/twaalgos/minimize.hh,
src/twaalgos/neverclaim.cc, src/twaalgos/postproc.cc,
src/twaalgos/postproc.hh, src/twaalgos/powerset.cc,
src/twaalgos/powerset.hh, src/twaalgos/randomgraph.cc,
src/twaalgos/remprop.cc, src/twaalgos/remprop.hh, src/twaalgos/stats.cc,
src/twaalgos/stats.hh, src/twaalgos/stutter.cc, src/twaalgos/stutter.hh,
src/twaalgos/translate.cc, src/twaalgos/translate.hh,
wrap/python/ajax/spotcgi.in, wrap/python/spot.py,
wrap/python/spot_impl.i, wrap/python/Makefile.am,
wrap/python/tests/automata-io.ipynb, wrap/python/tests/formulas.ipynb,
wrap/python/tests/ltl2tgba.py, wrap/python/tests/ltlparse.py,
wrap/python/tests/ltlsimple.py, wrap/python/tests/randltl.ipynb: Adjust
to use the new interface.
* src/sanity/style.test: Accept more C++11 patterns.
* NEWS: Mention the change.

* src/ltlparse/ltlscan.ll: Adjust parser.
* src/ltlvisit/print.cc: Adjust printer.
* src/tests/ltlfilt.test: Add some tests.
* NEWS: Mention it.

* src/bin/ltlfilt.cc: Add option --unabbreviate.
* src/tests/ltlfilt.test: Add a test case.
* NEWS: Mention it.

Fixes #39, reported by Joachim Klein.

* src/ltlvisit/lunabbrev.hh, src/ltlvisit/lunabbrev.cc: Take an option
to specify which of xor/equiv/implies should be rewritten.
* src/ltlvisit/print.cc (print_spin): Rewrite only xor.
* src/tests/ltlfilt.test: Add a test case.
* NEWS: Mention this.

* src/bin/common_output.cc: Add option -0.
* src/tests/ltlfilt.test: Test it.
* NEWS: Document it.

* README, configure.ac, iface/ltsmin/Makefile.am,
src/tests/defs.in, src/tests/.gitignore, src/tests/Makefile.am,
src/Makefile.am: update references.
* src/kripketest/.gitignore, src/kripketest/Makefile.am,
src/kripketest/defs.in, src/graphtest/.gitignore,
src/graphtest/Makefile.am,
src/graphtest/defs.in, src/ltltest/.cvsignore,
src/ltltest/.gitignore, src/ltltest/Makefile.am,
src/ltltest/defs.in:: remove files.
* src/kripketest/bad_parsing.test, src/kripketest/kripke.test,
src/kripketest/origin, src/kripketest/parse_print_test.cc,
src/ltltest/bare.test, src/ltltest/consterm.cc,
src/ltltest/consterm.test, src/tests/defs.in,
src/ltltest/equals.test, src/ltltest/equalsf.cc,
src/ltltest/eventuniv.test, src/ltltest/exclusive-ltl.test,
src/graphtest/graph.cc, src/graphtest/graph.test,
src/ltltest/isop.test, src/ltltest/kind.cc,
src/ltltest/kind.test, src/ltltest/latex.test,
src/ltltest/lbt.test, src/ltltest/length.cc,
src/ltltest/length.test, src/ltltest/lenient.test,
src/ltltest/ltlcrossgrind.test, src/ltltest/ltlfilt.test,
src/ltltest/ltlgrind.test, src/ltltest/ltlrel.cc,
src/ltltest/ltlrel.test, src/ltltest/lunabbrev.test,
src/ltltest/nenoform.test, src/graphtest/ngraph.cc,
src/graphtest/ngraph.test, src/ltltest/parse.test,
src/ltltest/parseerr.test, src/ltltest/rand.test,
src/ltltest/readltl.cc, src/ltltest/reduc.cc,
src/ltltest/reduc.test, src/ltltest/reduc0.test,
src/ltltest/reduccmp.test, src/ltltest/reducpsl.test,
src/ltltest/remove_x.test, src/ltltest/stutter-ltl.test,
src/ltltest/syntimpl.cc, src/ltltest/syntimpl.test,
src/graphtest/tgbagraph.test, src/ltltest/tostring.cc,
src/ltltest/tostring.test, src/ltltest/tunabbrev.test,
src/ltltest/tunenoform.test, src/graphtest/twagraph.cc,
src/ltltest/unabbrevwm.test,src/ltltest/utf8.test,
src/ltltest/uwrm.test: rename as...
* src/tests/bad_parsing.test, src/tests/kripke.test,
src/tests/origin, src/tests/parse_print_test.cc,
src/tests/bare.test, src/tests/consterm.cc,
src/tests/consterm.test, src/tests/equals.test,
src/tests/equalsf.cc, src/tests/eventuniv.test,
src/tests/exclusive-ltl.test, src/tests/graph.cc,
src/tests/graph.test, src/tests/isop.test,
src/tests/kind.cc, src/tests/kind.test,
src/tests/latex.test, src/tests/lbt.test,
src/tests/length.cc, src/tests/length.test,
src/tests/lenient.test, src/tests/ltlcrossgrind.test,
src/tests/ltlfilt.test, src/tests/ltlgrind.test,
src/tests/ltlrel.cc, src/tests/ltlrel.test,
src/tests/lunabbrev.test, src/tests/nenoform.test,
src/tests/ngraph.cc, src/tests/ngraph.test,
src/tests/parse.test, src/tests/parseerr.test,
src/tests/rand.test, src/tests/readltl.cc,
src/tests/reduc.cc, src/tests/reduc.test,
src/tests/reduc0.test, src/tests/reduccmp.test,
src/tests/reducpsl.test, src/tests/remove_x.test,
src/tests/stutter-ltl.test, src/tests/syntimpl.cc,
src/tests/syntimpl.test, src/tests/tgbagraph.test,
src/tests/tostring.cc, src/tests/tostring.test,
src/tests/tunabbrev.test, src/tests/tunenoform.test,
src/tests/twagraph.cc, src/tests/unabbrevwm.test,
src/tests/utf8.test, src/tests/uwrm.test: ...these!

* src/bin/ltlfilt.cc: Implement it.
* src/bin/common_output.cc, src/bin/common_output.hh: export the
stream_formula function.
* src/ltltest/ltlfilt.test: Test it.
* src/ltlvisit/relabel.hh: Make it possible to clear the
relabeling map.
* NEWS, doc/org/ltlfilt.org: Mention --define.

* src/bin/common_output.cc, src/bin/common_output.hh: Add option
--output.
* src/ltltest/ltlfilt.test, src/ltltest/rand.test: Add tests.
* NEWS, doc/org/ioltl.org: Document it.

* src/bin/common_output.cc, src/bin/common_output.hh:
Add count_output.
* src/bin/ltlfilt.cc: Add the --count option.
* src/ltltest/ltlfilt.test: Test it.
* NEWS: Mention it.

* src/misc/bitvect.hh: Here.
* src/tgbatest/det.test, src/ltltest/ltlfilt.test: Add test cases.

* src/sanity/style.test: Test for the missing header.
* iface/ltsmin/check.test, src/kripketest/kripke.test,
src/kripketest/parse_print_test.cc, src/ltlparse/fmterror.cc,
src/ltltest/consterm.test, src/ltltest/kind.test,
src/ltltest/length.test, src/ltltest/ltlfilt.test,
src/ltltest/reduc.cc, src/ltltest/reduc.test,
src/ltltest/reduc0.test, src/ltltest/reducpsl.test,
src/ltltest/remove_x.test, src/ltltest/unabbrevwm.test,
src/ltltest/utf8.test, src/ltltest/uwrm.test, src/ltlvisit/dump.cc,
src/ltlvisit/remove_x.cc, src/misc/casts.hh, src/misc/fixpool.hh,
src/misc/hashfunc.hh, src/misc/ltstr.hh, src/sanity/readme.test,
src/taalgos/tgba2ta.cc, src/tgbaalgos/bfssteps.cc,
src/tgbaalgos/stats.cc, src/tgbatest/acc.test,
src/tgbatest/bitvect.test, src/tgbatest/complementation.test,
src/tgbatest/cycles.test, src/tgbatest/degendet.test,
src/tgbatest/dfs.test, src/tgbatest/dupexp.test,
src/tgbatest/emptchkr.test, src/tgbatest/intvcomp.test,
src/tgbatest/ltl2ta.test, src/tgbatest/ltl2ta2.test,
src/tgbatest/ltlprod.test, src/tgbatest/maskacc.test,
src/tgbatest/obligation.test, src/tgbatest/randpsl.test,
src/tgbatest/readsat.cc, src/tgbatest/readsat.test,
src/tgbatest/scc.test, src/tgbatest/sccsimpl.test,
src/tgbatest/taatgba.test, src/tgbatest/tgbaread.test,
src/tgbatest/tripprod.test, src/tgbatest/uniq.test,
src/tgbatest/wdba.test: Add it.

* src/ltlparse/ltlscan.ll: Skip comments.
* src/ltltest/ltlfilt.test: Test this.
* NEWS: Mention it.

* src/ltltest/ltlfilt.test: Add more tests.
* src/ltltest/stutter.test: New test.
* src/ltltest/Makefile.am: Adjust.
* src/bin/ltlfilt.cc: Catch std::runtime_error.
* src/tgba/tgbasl.hh (make_tgbasl): New function.
* src/tgba/tgbagraph.hh (make_tgba_graph): Add another overload.
* src/tgbaalgos/stutter_invariance.cc,
src/tgbaalgos/stutter_invariance.hh: Take the algorithm version as an
optional integer, and call getenv() only once.
* bench/stutter/stutter_invariance_randomgraph.cc,
bench/stutter/stutter_invariance_formulas.cc: Simplify using the
above functions.

* src/ltlast/multop.cc, src/ltlast/multop.hh (multop::boolean_operands,
multop::boolean_count): New methods.
* src/ltlvisit/relabel.cc, src/ltlvisit/relabel.hh
(relabel): Take an optional relabeling_map as parameter.
(relabel_bse): New.
* src/ltltest/ltlrel.test, src/ltltest/ltlrel.cc: New files.
* src/ltltest/Makefile.am: Add them.
* src/bin/ltlfilt.cc: Add option --relabel-bool.
* src/ltltest/ltlfilt.test: Test it.
* NEWS: Mention it.
* doc/org/ltlfilt.org: Illustrate it.

This helps recursive implication checks.  Also order
atomic propositions with strverscmp().

* src/ltlast/formula.hh (formula_ptr_less_than_multop,
is_literal, atomic_prop_cmp): New.
* src/ltlast/formula.cc (is_literal, atomic_prop_cmp): Implement them.
* src/ltlast/multop.cc: Use formula_ptr_less_than_multop.
* src/ltltest/isop.test, src/ltltest/ltlfilt.test,
src/tgbatest/det.test, src/tgbatest/dstar.test,
src/tgbatest/explicit.test, src/tgbatest/explpro2.test,
src/tgbatest/explpro3.test, src/tgbatest/explprod.test,
src/tgbatest/nondet.test, src/tgbatest/tripprod.test: Adjust tests.
* NEWS: Mention the new order.

* src/bin/common_finput.cc: Here.
* src/ltltest/ltlfilt.test: Test it.
* NEWS: Mention it.