Blender Git Loki

Grease Pencil Bugfixs:

- Eraser now works in Sequence Editor. Cleaned up the code that handles Sequencer coordinate-conversions so that it should be a bit faster (doesn't need to recalculate offsets+scaling for every point that is made).

- Fixed mistake made in previous commit that made the pressure value (for tablets) an integer instead or a float. This should solve some of the reports of bits of strokes being missed on tablets.