* Added a new Paint type in scene DNA. This is now the base struct for Sculpt.
* The Paint type contains a list of Brushes, you can add or remove these much like material and texture slots.
* Modified the UI for the new Paint type, now shows the list of brushes active for this mode
* Added a New Brush operator, shows in the UI as a list of brush tool types to add
* Made the sculpt tool property UI smaller and not expanded, expectation is that we will have a number of preset brushes that will cover the basic sculpt brush types
TODO:
* Vertex paint, weight paint, texture paint need to be converted to this system next
* Add brush presets to the default blend
* Image painting back. 2d paint, 3d paint and projection, undo,
pressure, repeating paint operations, etc should all work.
Drawing cursor needs a bit of work, only gets shown when enabling
texture paint mode now.
* Move sculpt, image paint, and vertex/weight paint into a single
sculpt_paint module. Doesn't make much difference now, but nice
to have it together for better integration and consistency in
the future.
