Reworked checkAssumptions and started work on first tests

src/main/scala/inox/ast/DSL.scala

src/main/scala/inox/package.scala

src/main/scala/inox/solvers/EnumerationSolver.scala

src/main/scala/inox/solvers/SimpleSolverAPI.scala

src/main/scala/inox/solvers/Solver.scala

src/main/scala/inox/solvers/SolverResponses.scala

...main/scala/inox/solvers/combinators/PortfolioSolver.scala

src/main/scala/inox/solvers/combinators/TimeoutSolver.scala

src/main/scala/inox/solvers/smtlib/SMTLIBSolver.scala

src/main/scala/inox/solvers/unrolling/Templates.scala

src/main/scala/inox/solvers/unrolling/UnrollingSolver.scala

src/main/scala/inox/solvers/z3/AbstractZ3Solver.scala

src/main/scala/inox/solvers/z3/NativeZ3Solver.scala

src/main/scala/inox/solvers/z3/UninterpretedZ3Solver.scala

src/test/scala/inox/InoxTestSuite.scala

src/test/scala/inox/SolvingTestSuite.scala

src/test/scala/inox/TestSilentReporter.scala

src/test/scala/inox/regression/SimpleQuantifiersSuite.scala

src/test/scala/inox/regression/SimpleSolversSuite.scala

src/test/scala/inox/unit/evaluators/EvaluatorSuite.scala