#1006 CIF controller checker's confluence check: interleave 'zero' variables

• Best to review per commit.
• End-user visible changes:
  • The performance of the confluence check has been greatly improved, by interleaving the internally added 'zero' BDD variables.
  • A BDD variable leak in computing edge support variable sets has been fixed, which may slightly improve the performance of data-based synthesis and the controller checker.
• Other changes:
  • Fixed some types in variables names of the confluence check code.
  • CIF to BDD conversion allows adding extra BDD domains for all variables.
• Performance:
  • Waterway lock (CIF benchmark): < 2s
  • Locomobiel MCC (RWS confidential model): < 15s
  • Lock Linne (RWS confidential model): ~ 2m51s

Closes #1006 (closed)