Blender Git Loki

* overlay now works in FIXED mapping mode
* overlay now just loads alpha and purely uses transparency to show strength (this eliminate dark borders on the overlay)
* overlay now shows when cursor is in viewport, not just when it is over the model (full time display operator is coming soon)
* when in fixed mapping mode, the curve fall off is included in the overlay (I'll give option to do that with tiled mode later, but requires multitexture)
* rake and pressure resizing are taken into account
* in fixed mode an attempt is made to only allocate as big a texture as needed for the brush size, and it doesn't resample if the brush shrinks
* rotation and offset are baked into the texture because emulating everything blender can do with textures in opengl would require a lot of code (same will eventually be done with texcache, which will make it even faster)