A tgba can now annotate a transition (i.e., the position of a
tgba_succ_iterator) with some string. This comes handy to associate that transition to its high-level name. * src/tgba/tgba.hh, src/tgba/tgba.cc (tgba::transition_annotation): New method. * src/tgba/tgbaproduct.hh, src/tgba/tgbaproduct.cc (tgba_product::transition_annotation): Implement it. * src/tgba/tgbatba.hh, src/tgba/tgbatba.cc (tgba_tba_proxy::transition_annotation): Likewise. * src/tgbaalgos/replayrun.cc (print_annotation): New function. (replay_tgba_run): Use it.