Blender Git Loki

Various Transform bugfixes.

- Trackball rotate was missing the NoConstraints flag
- Zooming didn't recalculate the 2D center correctly
- Zooming in transform was sending event to the 3D window even when working on UVs. (disabled when working on UVs for now, will need to send events to a 2D window handler eventually)
- In camera mode, when the selection was exactly on the camera, initgrabz was barfing, fallback to 1.0 now, which gives ok results.