Start rendering on rotate / zoom
Extract shape from Python object in RenderWorker
Dummy image now being displayed in scene
Rendering is now happening (but matrices are wrong)
Make axes of length 1 (unit)
Fix transform map operation

(facepalm forever)
Simpler matrix multiplication (since there's no translation)

Conflicts:
	src/render/render_worker.cpp
Rendering now appears to work.
(for 3D shapes only at the moment)