Changes to be committed:
	deleted:    ppcad/CADCommand.py
	new file:   ppcad/PPModuleBase.py
	modified:   ppcad/ppcad.py
	new file:   ppcad/ppmodules/PPHome.py
	renamed:    ppcad/ppmodules/QuitCAD.py -> ppcad/ppmodules/toplevel/QuitCAD.py
	renamed:    ppcad/ppmodules/TestButtons.py -> ppcad/ppmodules/toplevel/TestButtons.py
	new file:   ppcad/ppmodules/toplevel/__init__.py