Pure Python korlib

Yeah, korlib was a bit faster than this implementation, but, honestly,
having a second python module made life more difficult than it needed to
be. This fixes that.
Fix #5

We now harvest information about texture images throughout the export
process and don't pull the trigger until we're totally done. There are
still some issues with regard to confusing UI, but we'll get to it.
Update DSpan finalize log messages

They now match what we do in the texture management things and stuff
Basic collision modifier

This basic collision modifier supports sphere bounds and triangle mesh
bounds. We still need to decide if things like calcSphereBounds belong in
libHSPlasma or if they should live in korlib.