restructure the complementation code

The previous code was sometime doing the work of remove_fin() in
addition to complementing the acceptance conditions.  This separate
the two operations clearly.  Also the specialized code for
complementing weak automata is now a specialized code for remove_fin()
on weak automata.

* src/twaalgos/dtgbacomp.hh, src/twaalgos/dtgbacomp.cc: Rename as ...
* src/twaalgos/complement.hh, src/twaalgos/complement.cc: ... these.
* src/twaalgos/Makefile.am: Adjust.
* src/twaalgos/complement.hh (dtgba_complement): Rename as ...
(dtwa_complement): ... this, and restrict the purpose to completion
and accetance complementation.  Further acceptance simplification
can be done with remove_fin() and to_generalized_buchi().
* src/twaalgos/remfin.cc (remove_fin): Specialize handling of weak
automata using the code that was originally in dtgba_complement().
Also mark the output as state-based when the input has to Inf.
* src/twaalgos/postproc.cc, src/twaalgos/postproc.hh: Make sure
scc_filter is always called after to_generalized_buchi().
* bench/stutter/stutter_invariance_randomgraph.cc,
src/bin/ltlcross.cc, src/tests/ikwiad.cc, src/twaalgos/minimize.cc,
src/twaalgos/powerset.cc, src/twaalgos/stutter.cc: Adjust usage.
* src/tests/dstar.test, src/tests/ltl2dstar4.test,
src/tests/remfin.test: Adjust expected outputs.
* wrap/python/spot_impl.i: Export dtwa_complement().

src/twaalgos/Makefile.am

@@ -33,10 +33,10 @@ twaalgos_HEADERS = \
   canonicalize.hh \
   cleanacc.hh \
   complete.hh \
+  complement.hh \
   compsusp.hh \
   copy.hh \
   cycles.hh \
-  dtgbacomp.hh \
   degen.hh \
   dot.hh \
   dtbasat.hh \
@@ -90,10 +90,10 @@ libtwaalgos_la_SOURCES = \
   canonicalize.cc \
   cleanacc.cc \
   complete.cc \
+  complement.cc \
   compsusp.cc \
   copy.cc \
   cycles.cc \
-  dtgbacomp.cc \
   degen.cc \
   dot.cc \
   dtbasat.cc \