Blender Git Loki

Scripts:
- Updated ac3d exporter to use first material found in the mesh for loose edges (lines) color. Inspired by bug report from Stewart Andreason. Also made a few updates to very old parts of the code, got rid of two "try/except".

- Updated ac3d importer to be even more forgiving to bad data. Also added option to turn transparency on in the 3D View for models using materials with alpha < 1.0. Added optional support for ac3d's subdiv tag, works by adding a subsurf modifier to the imported model(s) that have this tag, so they appear as intended.