new rewriting of pattern-matching! rejoice!

src/funcheck/CodeExtraction.scala

src/orderedsets/RPrettyPrinter.scala

src/orderedsets/TreeOperations.scala

src/orderedsets/Unifier.scala

src/orderedsets/UnifierMain.scala

src/purescala/Analysis.scala

src/purescala/Common.scala

src/purescala/DefaultTactic.scala

src/purescala/PrettyPrinter.scala

src/purescala/Trees.scala

src/purescala/TrivialSolver.scala

src/purescala/TypeTrees.scala

src/purescala/Z3Solver.scala