Port ScalaZ3 to sbt 0.12

Implement the necessary changes, mainly in sbt, rework library directory
For now it only includes 64b-unix z3.
ScalaZ3 for Scala 2.10
Fix dependency to Scalatest
Remove failing tests over unsupported features and spurious output
When not within a jar, we load libscalaz3.so in CWD/lib-bin, for sbt test
Add support for getting UNSAT proofs via Solver.getProof
Add openLog for debugging and replay purposes
merging upstream