* Initial version of a property test framework (javaslang.test) based on
predicate logic. Next: More quantors and boolean operators.
* Initial version of a code generator. Parts of the property test
framework are generated. Next: Generate Tuples and Function (also add
CheckedFunctions etc.)
* IStream will move to javaslang.collection. Collections and IStream
will have common interfaces (for monadic operations, traversal, etc.)