This is a huge patch.  tgba_digraph are equiped with some boolean
properties that can be used to indicate whether they represent SBA
(and will carry more informations later).  All algorithms that produce
or use sba_explicit_* automata are changed to use tgba_digraph.
postproc has been rewritten using only tgba_digraph, and this required
changing the return types of many algorithms from tgba* to
tgba_digraph*.

* src/bin/dstar2tgba.cc, src/bin/ltlfilt.cc, src/dstarparse/dra2ba.cc,
src/dstarparse/dstar2tgba.cc, src/dstarparse/nra2nba.cc,
src/dstarparse/nsa2tgba.cc, src/dstarparse/public.hh,
src/tgba/tgbagraph.hh, src/tgba/tgbasafracomplement.cc,
src/tgbaalgos/compsusp.cc, src/tgbaalgos/compsusp.hh,
src/tgbaalgos/degen.cc, src/tgbaalgos/degen.hh,
src/tgbaalgos/dotty.cc, src/tgbaalgos/minimize.cc,
src/tgbaalgos/minimize.hh, src/tgbaalgos/postproc.cc,
src/tgbaalgos/postproc.hh, src/tgbaalgos/sccfilter.cc,
src/tgbaalgos/sccinfo.cc, src/tgbaalgos/stripacc.cc,
src/tgbaalgos/stripacc.hh, src/tgbaalgos/translate.cc,
src/tgbaalgos/translate.hh, src/tgbatest/ltl2tgba.cc,
wrap/python/spot.i: Update.

* src/dstarparse/dra2ba.cc: Use tgba_digraph instead of
tgba_explicit_number.
* src/tgbatest/dstar.test: Adjust.

* src/dstarparse/dstarparse.yy, src/dstarparse/public.hh: Adjust the
parser to build a tgba_digraph.
* src/dstarparse/dra2ba.cc, src/dstarparse/nra2nba.cc,
src/dstarparse/nsa2tgba.cc: Temporarily adjust these functions to the
new type until they are rewritten.

* src/sanity/style.test: Add a test.
* iface/dve2/dve2.cc, iface/dve2/dve2check.cc, src/bin/common_output.cc,
src/bin/dstar2tgba.cc, src/bin/ltl2tgba.cc, src/bin/ltlcross.cc,
src/dstarparse/dra2ba.cc, src/dstarparse/fmterror.cc,
src/dstarparse/nsa2tgba.cc, src/kripke/kripkeprint.cc,
src/kripkeparse/fmterror.cc, src/ltlast/atomic_prop.cc,
src/ltlast/bunop.cc, src/ltltest/ltlrel.cc, src/ltltest/reduc.cc,
src/ltltest/syntimpl.cc, src/ltlvisit/dotty.cc, src/ltlvisit/lbt.cc,
src/ltlvisit/randomltl.cc, src/ltlvisit/relabel.cc,
src/ltlvisit/simplify.cc, src/ltlvisit/tostring.cc, src/misc/bitvect.cc,
src/misc/optionmap.cc, src/misc/timer.cc, src/neverparse/fmterror.cc,
src/priv/freelist.cc, src/saba/sabacomplementtgba.cc,
src/sabaalgos/sabadotty.cc, src/taalgos/dotty.cc,
src/taalgos/minimize.cc, src/tgba/bdddict.cc, src/tgba/bddprint.cc,
src/tgba/futurecondcol.cc, src/tgba/taatgba.hh,
src/tgba/tgbakvcomplement.cc, src/tgba/tgbasafracomplement.cc,
src/tgbaalgos/compsusp.cc, src/tgbaalgos/cycles.cc,
src/tgbaalgos/dotty.cc, src/tgbaalgos/dtbasat.cc,
src/tgbaalgos/dtgbasat.cc, src/tgbaalgos/emptiness.cc,
src/tgbaalgos/gtec/gtec.cc, src/tgbaalgos/gv04.cc,
src/tgbaalgos/lbtt.cc, src/tgbaalgos/ltl2tgba_fm.cc,
src/tgbaalgos/minimize.cc, src/tgbaalgos/neverclaim.cc,
src/tgbaalgos/powerset.cc, src/tgbaalgos/replayrun.cc,
src/tgbaalgos/save.cc, src/tgbaalgos/scc.cc, src/tgbaalgos/sccfilter.cc,
src/tgbaalgos/weight.cc, src/tgbaalgos/word.cc,
src/tgbaparse/fmterror.cc, src/tgbatest/bitvect.cc,
src/tgbatest/complementation.cc, src/tgbatest/intvcmp2.cc,
src/tgbatest/intvcomp.cc, src/tgbatest/ltl2tgba.cc,
src/tgbatest/randtgba.cc: Replace << "c" by << 'c' when
appropriate.

Extended former conversion from DRA->DBA to handle
the case where some SCC is not DBA-realizable.

* src/dstarparse/dra2dba.cc: Rename as...
* src/dstarparse/dra2ba.cc: ... this.
(dra_to_dba, dra_to_dba_worker): Rename as...
(dra_to_ba, dra_to_ba_worker): ... these and extend.
* src/dstarparse/Makefile.am, src/dstarparse/public.hh,
src/dstarparse/dstar2tgba.cc, src/dstarparse/nra2nba.cc: Adjust.
* NEWS: Update the description of dstar2tgba accordingly.

This is an implementation of Krishnan's ISAAC'94 paper to convert
deterministic Rabin automata into DBA when possible.

* src/dstarparse/dra2dba.cc: New file.
* src/dstarparse/dstar2tgba.cc: New file.
* src/dstarparse/Makefile.am: Add them.
* src/dstarparse/nra2nba.cc (nra_to_nba): Adjust so
that dra_to_dba() can call it using a masked automaton.
* src/dstarparse/public.hh (dra_to_dba, dstar_to_tgba): Declare.
* src/tgbatest/ltl2tgba.cc: Add an -XDD option.
* src/tgbatest/dstar.test: More tests.