-eALGO and -EALGO to ease the addition of new algorithms.
* src/tgbatest/emptchk.test, src/tgbatest/emptchke.test: Adjust.

New function, variant of emptiness_check::check().
* src/tgbaalgos/emptinesscheck.hh (emptiness_check::check2):
Likewise.
* src/tgbatest/emptchk.test, src/tgbatest/emptchke.test: Exercize -e2.
* src/tgbatest/ltl2tgba.cc: Support -e2, for emptiness_check::check2().
* iface/gspn/Makefile.am [WITH_GSPN_EESRG] (check_PROGRAMS):
Compile ltlgspn-eesrg instead of ltleesrg.
(ltleesrg_SOURCES, ltleesrg_LDADD): Replace by...
(ltlgspn_eesrg_SOURCES, ltlgspn_eesrg_LDADD, LIBGSPNESRG_LDFLAGS):
... these.
* iface/gspn/ltleesrg.cc: Delete.
* iface/gspn/ltlgspn.cc [EESRG]: Support EESRG conditionally.
Support -e2.

* src/tgbatest/defs.in (VALGRIND, run): Define.
* src/tgbatest/bddprod.test, src/tgbatest/dupexp.test,
src/tgbatest/emptchk.test, src/tgbatest/emptchke.test,
src/tgbatest/explicit.test, src/tgbatest/explpro2.test,
src/tgbatest/explpro3.test, src/tgbatest/explprod.test,
src/tgbatest/ltl2tgba.test, src/tgbatest/ltlprod.test,
src/tgbatest/mixprod.test, src/tgbatest/readsave.test,
src/tgbatest/tgbaread.test, src/tgbatest/tripprod.test: Use run().

arcs.  ltl2tgba_fm benefits from this and join multiple arcs with
the same destination and acceptance conditions.
* src/tgba/formula2bdd.cc, src/tgba/formula2bdd.hh: New files.
* src/tgba/Makefile.am (tgba_HEADERS, libtgba_la_SOURCES): Add them.
* src/tgba/bddprint.cc, src/tgba/bddprint.hh (bdd_pring_formula,
bdd_format_formula): New functions.
* src/tgba/tgbaexplicit.hh (tgba_explicit::get_condition,
tgba_explicit::add_condition, tgba_explicit::add_neg_condition,
tgba_explicit::declare_accepting_condition,
tgba_explicit::has_accepting_condition,
tgba_explicit::get_accepting_condition,
tgba_explicit::add_accepting_condition): Take a const formula*.
* src/tgba/tgbaexplicit.cc (tgba_explicit::add_condition):
Rewrite using formula_to_bdd.
* src/tgbaalgos/dotty.cc (dotty_bfs::process_link): Use
bdd_print_formula to display conditions.
* src/tgbaalgos/save.cc (save_bfs::process_state): Likewise.
* src/tgbaalgos/ltl2tgba_fm.cc (translate_dict::bdd_to_formula):
New function.
(translate_dict::conj_bdd_to_atomic_props): Remove.
(ltl_to_tgba_fm): Factor successors on accepting conditions
and destinations, not conditions.  Use bdd_to_formula to translate
the conditions.
* src/tgbaparse/tgbaparse.yy: Expect conditions as a formula
in a string, call the LTL parser for this.
* src/tgbaparse/tgbascan.ll: Process " and \ escapes in
strings.
* src/tgbatest/emptchke.test, src/tgbatest/explicit.test,
src/tgbatest/explpro2.test, src/tgbatest/explpro3.test,
src/tgbatest/explprod.test, src/tgbatest/mixprod.test,
src/tgbatest/readsave.test, src/tgbatest/tgbaread.test,
src/tgbatest/tripprod.test: Adjust to new syntax for explicit
automata.

* Makefile.am, configure.ac, doc/Makefile.am, iface/Makefile.am,
iface/gspn/Makefile.am, iface/gspn/common.cc,
iface/gspn/common.hh, iface/gspn/dottyeesrg.cc,
iface/gspn/dottygspn.cc, iface/gspn/eesrg.cc, iface/gspn/eesrg.hh,
iface/gspn/gspn.cc, iface/gspn/gspn.hh, iface/gspn/ltlgspn.cc,
src/Makefile.am, src/ltlast/Makefile.am, src/ltlast/allnodes.hh,
src/ltlast/atomic_prop.cc, src/ltlast/atomic_prop.hh,
src/ltlast/binop.cc, src/ltlast/binop.hh, src/ltlast/constant.cc,
src/ltlast/constant.hh, src/ltlast/formula.cc,
src/ltlast/formula.hh, src/ltlast/multop.cc, src/ltlast/multop.hh,
src/ltlast/predecl.hh, src/ltlast/refformula.cc,
src/ltlast/refformula.hh, src/ltlast/unop.cc, src/ltlast/unop.hh,
src/ltlast/visitor.hh, src/ltlenv/Makefile.am,
src/ltlenv/defaultenv.cc, src/ltlenv/defaultenv.hh,
src/ltlenv/environment.hh, src/ltlparse/Makefile.am,
src/ltlparse/fmterror.cc, src/ltlparse/ltlparse.yy,
src/ltlparse/ltlscan.ll, src/ltlparse/parsedecl.hh,
src/ltlparse/public.hh, src/ltltest/Makefile.am,
src/ltltest/defs.in, src/ltltest/equals.cc,
src/ltltest/equals.test, src/ltltest/lunabbrev.test,
src/ltltest/nenoform.test, src/ltltest/parse.test,
src/ltltest/parseerr.test, src/ltltest/readltl.cc,
src/ltltest/tostring.cc, src/ltltest/tostring.test,
src/ltltest/tunabbrev.test, src/ltltest/tunenoform.test,
src/ltlvisit/Makefile.am, src/ltlvisit/clone.cc,
src/ltlvisit/clone.hh, src/ltlvisit/destroy.cc,
src/ltlvisit/destroy.hh, src/ltlvisit/dotty.cc,
src/ltlvisit/dotty.hh, src/ltlvisit/dump.cc, src/ltlvisit/dump.hh,
src/ltlvisit/lunabbrev.cc, src/ltlvisit/lunabbrev.hh,
src/ltlvisit/nenoform.cc, src/ltlvisit/nenoform.hh,
src/ltlvisit/postfix.cc, src/ltlvisit/postfix.hh,
src/ltlvisit/tostring.cc, src/ltlvisit/tostring.hh,
src/ltlvisit/tunabbrev.cc, src/ltlvisit/tunabbrev.hh,
src/misc/Makefile.am, src/misc/bddalloc.cc, src/misc/bddalloc.hh,
src/misc/bddlt.hh, src/misc/hash.hh, src/misc/minato.cc,
src/misc/minato.hh, src/misc/version.cc, src/misc/version.hh,
src/tgba/Makefile.am, src/tgba/bdddict.cc, src/tgba/bdddict.hh,
src/tgba/bddprint.cc, src/tgba/bddprint.hh, src/tgba/public.hh,
src/tgba/state.hh, src/tgba/statebdd.cc, src/tgba/statebdd.hh,
src/tgba/succiter.hh, src/tgba/succiterconcrete.cc,
src/tgba/succiterconcrete.hh, src/tgba/tgba.cc, src/tgba/tgba.hh,
src/tgba/tgbabddconcrete.cc, src/tgba/tgbabddconcrete.hh,
src/tgba/tgbabddconcretefactory.cc,
src/tgba/tgbabddconcretefactory.hh,
src/tgba/tgbabddconcreteproduct.cc,
src/tgba/tgbabddconcreteproduct.hh, src/tgba/tgbabddcoredata.cc,
src/tgba/tgbabddcoredata.hh, src/tgba/tgbabddfactory.hh,
src/tgba/tgbaexplicit.cc, src/tgba/tgbaexplicit.hh,
src/tgba/tgbaproduct.cc, src/tgba/tgbaproduct.hh,
src/tgba/tgbatba.cc, src/tgba/tgbatba.hh,
src/tgbaalgos/Makefile.am, src/tgbaalgos/dotty.cc,
src/tgbaalgos/dotty.hh, src/tgbaalgos/dupexp.cc,
src/tgbaalgos/dupexp.hh, src/tgbaalgos/emptinesscheck.cc,
src/tgbaalgos/emptinesscheck.hh, src/tgbaalgos/lbtt.cc,
src/tgbaalgos/lbtt.hh, src/tgbaalgos/ltl2tgba_fm.cc,
src/tgbaalgos/ltl2tgba_fm.hh, src/tgbaalgos/ltl2tgba_lacim.cc,
src/tgbaalgos/ltl2tgba_lacim.hh, src/tgbaalgos/magic.cc,
src/tgbaalgos/magic.hh, src/tgbaalgos/reachiter.cc,
src/tgbaalgos/reachiter.hh, src/tgbaalgos/save.cc,
src/tgbaalgos/save.hh, src/tgbaparse/Makefile.am,
src/tgbaparse/fmterror.cc, src/tgbaparse/parsedecl.hh,
src/tgbaparse/public.hh, src/tgbaparse/tgbaparse.yy,
src/tgbaparse/tgbascan.ll, src/tgbatest/Makefile.am,
src/tgbatest/bddprod.test, src/tgbatest/defs.in,
src/tgbatest/dupexp.test, src/tgbatest/emptchk.test,
src/tgbatest/emptchke.test, src/tgbatest/explicit.test,
src/tgbatest/explpro2.test, src/tgbatest/explpro3.test,
src/tgbatest/explprod.test, src/tgbatest/ltl2tgba.test,
src/tgbatest/ltlprod.test, src/tgbatest/mixprod.test,
src/tgbatest/readsave.test, src/tgbatest/spotlbtt.test,
src/tgbatest/tgbaread.test, src/tgbatest/tripprod.test,
wrap/Makefile.am, wrap/python/Makefile.am, wrap/python/buddy.i,
wrap/python/spot.i, wrap/python/cgi/Makefile.am,
wrap/python/cgi/ltl2tgba.in, wrap/python/tests/Makefile.am,
wrap/python/tests/bddnqueen.py, wrap/python/tests/interdep.py,
wrap/python/tests/ltl2tgba.py, wrap/python/tests/ltl2tgba.test,
wrap/python/tests/ltlparse.py, wrap/python/tests/ltlsimple.py,
wrap/python/tests/run.in: Add Copyright license.

* src/tgbatest/Makefile.am (check_PROGRAMS): Remove
emptinesscheckexplicit.
(emptinesscheckexplicit_SOURCES): Remove.
(TESTS): Replace emptinesscheckexplicit.test by emptchke.test.
* src/tgbatest/emptinesscheckexplicit.cc,
src/tgbatest/emptinesscheckexplicit.test: Delete.
* src/tgbatest/empchke.test: New file.
* src/tgbatest/ltl2tgba.cc: Add support for -X.

* src/tgbatest/emptinesscheckexplicit.cc (main): New file.

* src/tgbatest/emptinesscheck.test: New file.

* src/tgbatest/emptinesscheck.cc (main): New file.

* src/tgbaalgos/emptinesscheck.cc (spot): New method.

* src/tgbaalgos/emptinesscheck.hh: New interface.