python: rewrite translate() to deal with unambiguous and sbacc
and make it easier to extend and use. * src/twaalgos/postproc.hh, src/twaalgos/translate.cc, src/twaalgos/translate.hh: Incorporate the Unambiguous option with the other preferences. It's cleaner this way, and the previous setup did not work well with Python. * src/bin/ltl2tgba.cc: Adjust to this change. * wrap/python/spot.py (translate): Rewrite. * wrap/python/tests/automata.ipynb: Adjust existing cases, and add more as well as some comments.