relabel_bse: rework to simplify more patterns
Rework the way we compute and use cut-points to catch more patterns we can rewrite. Also Use BDDs to check if a Boolean sub-expression is false or true. Fixes issue #540 (closed).
- spot/tl/relabel.hh: Update documentation
- spot/tl/relabel.cc (relabel_bse): Rework.
- tests/core/ltlfilt.test: Add more test cases.
- tests/python/_mealy.ipynb: Update.
- NEWS: Mention the change.