Fix bug in prop->cnf
Add remove tests command in test.lisp

As recommended by
<https://github.com/OdonataResearchLLC/lisp-unit/blob/master/lisp-unit.lisp>
Fix bug for 'iff in prop->cnf
Add option for prop-simplify to use minisat
Remove unused/redundant finite-set-map-cross

Use (curry #'map-finite-set-product 'nil) instead
Add fa-rewrite-edges
Merge commit '6bf0361' into dev