Clear the contaiment cache after -r7.
Doing so will release all BDD variables used by automata created for syntactic implication. This way the main translation will create acceptance variables again in a more natural order, which will help the degeneralization (until we get a better degeneralization). * src/ltlvisit/contain.cc, src/ltlvisit/contain.hh (language_containment_checker::clear): New method to clear the containment cache. * src/ltlvisit/simplify.cc, src/ltlvisit/simplify.hh (clear_as_bdd_cache): Also call language_containment_checker::clear.