Drop PyCXX from the build, update wads module

Unfortunately, it's not nearly as flexible as I need it to be, so it
looks like I'm going to have to write my own wrappers using pure
Python/C API functions.

- Slight bit of updating of the wads module, even though it doesn't
compile right now due to missing PyCXX. I will need to rewrite it to use
hand-written wrappers next.