adapting mutabelle

adapting SML_Quickcheck

passing a term with free variables to the quickcheck tester functions instead of an lambda expression because this is more natural with passing further evaluation terms; added output of evaluation terms; added evaluation of terms in the exhaustive testing

extending the test data generators to take the evaluation terms as arguments

adding option of evaluating terms after invocation in quickcheck

adding eval option to quickcheck

handling a quite restricted set of functions in Quickcheck_Narrowing by an easy transformation

adding minimalistic setup and transformation to handle functions as data to enable naive function generation for Quickcheck_Narrowing

adding a simple datatype for representing functions in Quickcheck_Narrowing

extending code_int type more; adding narrowing instance for type int; added test case for int instance