fix regressions in entailment tests
undo forced partial instantiation of reachability axioms
change smtlib directory structure
add file name to SMT session names
Merge branch 'master' of https://github.com/wies/grasshopper
rename Psi predicate to inst-closure
play with reachability axioms
fix problem with set union applied to single set
experimental reachability axioms
starting work on fixing splTranslator.ml
merge fixes from master