[Bf-python] crasher in CVS with UV Face Select mode

[Ken Hughes]

Just came across a way to segfault Blender using the Python API:

If you are in UV Face Select mode and remove the active face, you'll get 
a segfault when you try to so anything again in the 3D window.  A quick 
look through the code didn't give me any good ideas how to avoid this: 
should we switch the 3D window out of edit mode if you delete the 
object?  Throw an exception?

Ken