Adding encoding of sha1 collision for the hashing example
Basic optimizations for ambqi : only normalize UF applied to variables, direct handling of NOT
Fixes to quantifiers rewriter to prevent miniscoping nested quantifiers.  Minor fixes to ambqi.  Preparation for CASC proof output.  Add NNF option.
Major simplifications to macros module.
Add variable ordering to ambqi.  Bug fix to macros. More preparation for CASC proofs.