initial draft of PyGTK-based GUI:
  * show 3d-model (with glitches)
  * load a file
  * designed a window for basic model-oriented tasks


git-svn-id: https://pycam.svn.sourceforge.net/svnroot/pycam/trunk@83 bbaffbd6-741e-11dd-a85d-61de82d9cad9