Each BSDF node now has a Normal input, which can be used to set a custom normal
for the BSDF, for example if you want to have only bump on one of the layers in
a multilayer material.
The Bump node can be used to generate a normal from a scalar value, the same as
what happens when you connect a scalar value to the displacement output.
Documentation has been updated with the latest changes:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes
Patch by Agustin Benavidez, some implementation tweaks by me.
* Fix missing update when editing objects with emission materials.
* Fix preview pass rendering set to 1 not showing full resolution.
* Fix CUDA runtime compiling failing due to missing cache directory.
* Use settings from first render layer for visibility and material override.
And a bunch of incomplete and still disabled code mostly related to closure
sampling.
* Add alpha pass output, to use set Transparent option in Film panel.
* Add Holdout closure (OSL terminology), this is like the Sky option in the
internal renderer, objects with this closure show the background / zero
alpha.
* Add option to use Gaussian instead of Box pixel filter in the UI.
* Remove camera response curves for now, they don't really belong here in
the pipeline, should be moved to compositor.
* Output full float values for rendering now, previously was only byte precision.
* Add a patch from Thomas to get a preview passes option, but still disabled
because it isn't quite working right yet.
* CUDA: don't compile shader graph evaluation inline.
* Convert tabs to spaces in python files.
