Blender Git Loki

More AO fun to play with:
- AO energy slider to control amount
- option "Use sky color" for colored AO. The horizon color will define
bottom diffuse color, the zenith works on top
- option "Use sky texture" will do a full sky render to define AO color

Please note that AO energy and color only is found when a ray does not
intersect. So for interior scenes make sure 'Dist' value is sufficient
low.

New also is:

- World "Map input" allows "Ang Map" (Angular mapping) which can be used
for 360 degree spherical maps, aka as Light Probes. Check samples here:
http://www.debevec.org/Probes/
Note that Blender doesn't support HDRI images yet, but option "Use sky tex"
already gives intersting results with such images

- World sky rendering with Image Textures now correctly filters and uses
antialiasing. Also noticable for raytrace mirror reflections

- World preview render for sky type "Real" now gives correct view as
defined by current used camera.

I tried to speed up AO tracing with coherence systems, none of it really
worked yet... time to tackle octree itself i guess!