v0.14.0

Changed

• In Modern, setting occurs_check=error makes a cycle-creating unification raise
  error(representation_error(term), occurs_check(Var, Term)) instead of
  error(occurs_check(Var, Term), _). This is a DotProlog extension choice: ISO defines neither
  the flag nor term as a representation flag. The rejected pair remains in the error's second
  argument, and the printed message is unchanged. Handlers for SWI-Prolog's form need updating.
  StrictIso rejects the extension flag. In both modes, ISO unify_with_occurs_check/2 fails
  when unification would create a cycle, including when Modern has occurs_check=error.