Fixes for the PixieDustTree

* Correct type conformance error in Method and Constructor.
* Add code generation tests (these will mostly compile, but will fail when attempting to execute them)
* Correct tagging redefined static methods as "DyMET" (dynamic).
* If the class of a variable is Object, when attempting to assign it an object of any given class (except System), it would fail.
* The compiler did not generate code for the return statement if there was nothing specified to return.
* Change RMEM's for PUSH 0, in order to reserve initialized memory. This ensures null pointer dereferences in objects and strings.