Add proposition-{tautology,equivalent}
Fix prop-simplify

  * Now recurses correctly
  * Also uses propositions-equivalent
Add de morgans laws in simplifications
Consider 'nil as unsatisfiable in minisat
Add finite-set-equivalent
Add pattern-lambda-else
Add gsymbol-equal
Add the new source files to the asd-file
Add more map functions for grammars
Generalize edge equivalence in fa comparisions
Backup commit