Blender Git Loki

bugfix #1119

When using MotionBlur, the rendered coordinates were not correctly
adjusted, causing visual artifacts using the new AO, but it was also
visible for normal ray-shadow, which didn't become anti-aliased in
Mblur render.

Solved it with 2 globals now, to pass on blur offset to renderloop.
Leave it that way... the entire method used to jitter/AA/blur stuff
needs revision.