* spot/twa/acc.hh, spot/twa/acc.cc (parse_acc_code): Rename as...
(acc_cond::acc_code): ... this, making it a lot easier to build
acceptance conditions from strings.
* NEWS: Mention the change.
* spot/twaalgos/dtwasat.cc, spot/bin/randaut.cc, spot/tests/acc.cc:
Adjust.
* wrap/python/tests/acc_cond.ipynb, wrap/python/tests/accparse.ipynb,
wrap/python/tests/accparse2.py: Simplify, but not completely to exercise
all variants.
* wrap/python/spot_impl.i: Make acc_code's constructor implicit.