Blender Git Loki

Improvements in Zmask feature of yesterday:

- zmask now allows to have solid faces included too
- ctrl+click on render-layer layers (whats in a name!) now works better

Here's the revised and extended doc:

http://www.blender.org/development/current-projects/changes-since-244/rendering-features/

It's a difficult to explain feature... but important for a good compo pipeline
here. Being tested still!