1. changed fol_type, it's not a string type anymore. 2. sort literals in clauses.
1. changed fol_type, it's not a string type anymore.
2. sort literals in clauses.

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle