Blender Git Loki

Added single column UI layouts

This changes the layout when the properties window gets too narrow to render the contents properly.

Currently implemented for render, scene, world, object and materials, but the rest can be done easily.
Here's a video for demonstration:

http://www.reynish.com/files/blender25/properties_resize.mov

It automatically detects the window width and then skips the indicators that tells the layout to go to the next column. It requires very minimal changes to the UI scripts so we don't have to maintain two versions of the layouts.