postproc: add a SBAcc option
Producing state-based acceptance is now part of the postprocessing routines. That means we can more easily simplify automata with state-based acceptance (using autfilt -S --small --high, for instance) and as as side-effect, ltl2tgba can produce GBA. However the result of ltl2tgba -S is often larger than that of ltl2tgba -B. * src/twaalgos/postproc.cc, src/twaalgos/postproc.hh: Implement the SBAcc option. * src/bin/common_post.cc, src/bin/common_post.hh: Implement -S. * src/bin/autfilt.cc, src/bin/dstar2tgba.cc, src/bin/ltl2tgba.cc, src/bin/ltl2tgta.cc, src/bin/ltldo.cc: Adjust. * src/tests/sim3.test: Augment test case. * NEWS, doc/org/ltl2tgba.org, doc/org/autfilt.org: Document it -S.