* spot/twa/acc.hh: Remove useless comment.
* spot/twaalgos/car.cc: Rewrite the implementation to try
  multiple algorithms and choose the best, add the possibility
  to force the order of the colors/pairs in LAR and use
  propagate_marks_here.
* spot/twaalgos/car.hh, tests/python/car.py: Create a new system of
  options for CAR.
* spot/twaalgos/degen.cc, spot/twaalgos/degen.hh: Add the possibility
  to forbid some marks in is_partially_degeneralizable.