#424 CIF to mCRL2: use new precondition checking framework.

• Best to review per commit.
• Pretty straight-forward step-by-step moving of preconditions to new precondition checker, and then adopting it.
• End-user visible changes:
  • The CIF to mCRL2 transformation has improved output in case of precondition violations.
  • The CIF to mCRL2 transformer documentation has some fixes for what is supported for unary and binary operators that result in boolean values.

Addresses #424 (closed)

changed milestone to %v5.0

added CIF TypeEnhancement labels

mentioned in issue #424 (closed)

approved this merge request

merged

mentioned in commit 61f75cc9