TODO:
	- move tests into ../../t during build ?
	- update with new embedding strategy
	- allow more signatures on call_sub()
	- fill in method documentation for Parrot::Interpreter and Parrot::PMC
	- store parent interpreter in Parrot::PMC objects
	- allow invoke() on appropriate Parrot::PMC objects directly
	- bless Parrot::PMC objects into appropriate subclasses if possible
	- allow overloading magic on Parrot::PMC objects
	- improve tests for failure conditions
