Added initial version of Princess interface.
Created by: ptrbman
-PrincessSolver.scala contains the wrapper code of an (incomplete) api towards princess. -princess.jar & scala-actors-2.11.0.jar A (special) version of Princess with support for Natural numbers (i.e., an ADT with Succ, isZero, Pred and constant zero.
Also changed SolverFactory s.t. it allows --solvers=princess to run with the new Princess backend.