pyPolyCSG library updated

I have updated the pyPolyCSG python constructive solid geometry library to use the most recent version of the Carve CSG library. The updates to Carve appear to make it significantly more robust as well as much faster.

The update to pyPolyCSG:

• Improves the robustness, at least on my existing scripts
• Improves the speed of performing Boolean operations
• Fixes a bug where vertex normals and texture coordinates were treated as vertices (thanks to Ryan Rix for finding this)
• Adds the ability to transform polyhedra by a 3x3 or 4x4 matrix (again thanks to Ryan Rix!)

You can get the updated version from github: https://github.com/jamesgregson/pyPolyCSG