temporary version with functions represented as uninterpreted z3

src/funcheck/CodeExtraction.scala

src/funcheck/Extractors.scala

src/purescala/AbstractZ3Solver.scala

src/purescala/Evaluator.scala

src/purescala/FairZ3Solver.scala

src/purescala/PrettyPrinter.scala

src/purescala/Trees.scala

src/purescala/TypeTrees.scala

src/purescala/Z3ModelReconstruction.scala

src/purescala/Z3Solver.scala