Blender Git Loki

Fixed Constraint projection code in perspective mode. When using a planar constraints, it follows the movement of the mouse exactly instead of just casting on the plane.
In user terms: the motion on screen of the selection follows the motion of the mouse pointer.

Gives some errors when the constraint plane is nearly perpendicular to the view port though.

Added a debug print function for 4D vectors to arithb.c

Optimised the 3D -> view projection functions in view.c (a bit).