* spot/misc/bitset.cc, spot/misc/bitset.hh (set, clear):
Turn asserts into exceptions.
* spot/twa/acc.hh (mark_t): As a consequence, the
constructor is not noexcept anymore.
* tests/core/acc.cc, tests/python/except.py: More tests.
The exception raised by << and >> when shifting mark_t by too many
bits are only enabled in SPOT_DEBUG, as those operations are quite
low-level. However we were always testing them, and although we
wanted them to be active in Python, it was not always the case.
* spot/twa/acc.hh: introduce max_accsets() as
a static constexpr method, so we can see it in Python.
* spot/misc/bitset.hh: Fix preprocessing directive
so the check is actually enabled when compiling the Python
bindings.
* bin/autcross.cc, bin/autfilt.cc, bin/ltlcross.cc: Use max_accsets().
* tests/core/acc.cc: Comment out the shifting exception when
SPOT_DEBUG is unset.
* tests/python/except.py: Make sure the exception is always raised in
Python.
* spot/misc/bitset.hh: add methods set() and clear()
* spot/twa/acc.hh: deprecate comparison of mark_t with unsigned, and
rely more on biset for efficiency
