Blender Git Loki

This commit includes my smoke work from previous weeks.

There are lots of changes in the code but here is a list of new things visible to users:
* A new "Adaptive Domain" setting. It makes smoke domain dynamically adapt to domain and fluid changes:
1) Domain resolution and size adapts to only cover areas where smoke is, so that as small domain as possible has to be calculated at a time. You can also add additional simulation cells around the original domain area if needed.
2) When you move the domain object during simulation you only move the smoke "boundaries". Smoke itself remains still. This way you can limit simulated area to stay around moving emitters etc.
* Domain is now rotatable. This means you are no longer need to align your simulation on x, y or z axis but you can freely rotate the domain to match the target area.
* Rotation and scaling also work during simulation with one limitation: Domain contents (smoke,fire) move with the domain.
* Smoke now uses the scene gravity setting, so you can change gravity direction if required.
* Added a new option for volume textures when "Generated" coordinates are used: "Map to Bounds". This maps texture coordinates to mesh bounding box allowing you to render adaptive domain content. It also solves issues with domains scaled in edit mode, so I'm considering to make this enabled by default.

Please note that this feature is not yet finished. I still have quite a few todos left and I'm sure there are still several bugs there.