Blender Git Loki

changes to projection painting
* initializing a bucket only initializes pixels from that bucket (was initializing all pixels in intersecting faces before which made large faces slow to paint onto)
* removed scanline functions, they are not as useful when initializing small areas.
* UV seam checking also sets the seam flag on the adjacent face to avoid double lookups.

TODO - uv seam bleed doesn't work in perspective mode.