use more appropriate encoding for Z3 TPTP, as confirmed by evaluation

added one more known Z3 failure

added config options to control two aspects of the translation, for evaluation purposes

added choice operator output for Satallax

rationalized option names -- mono becomes raw_mono and mangled becomes mono

handle nonmangled monomorphich the same way as mangled monomorphic when it comes to helper -- otherwise we can end up generating too tight type guards

avoid using ":" for anything but systematic type tag annotations, because Hurd's Metis gives it that special semantics

fixed bang encoding detection of which types to encode

lemma Compl_insert: "- insert x A = (-A) - {x}"

avoid variable clashes by properly incrementing indices