Create mock class that tracks API calls

[run4flat]

Now that the API supports calling drawing functions on subclassed Drawables, I can write a mock class that records when different functions get called, and their parameters. This way, I can write code that uses the PDL API and the standard Prima API and compare the results.

I think the best way to do this is to not record the order of property assignments, but rather to record the state of the object when a drawing operation takes place. This way I'm testing state, not implementation.