Blender Git Loki

Extended RNA support for mesh customdata property layers.

Support for user-defined customdata layers (named int, float, string
layers) was limited to polygon customdata. This is not accessible in
cycles because only tessfaces are used there. Furthermore the polygon
attributes were simply described as MeshFloatProperty, MeshIntProperty,
MeshStringProperty, omitting the distinction by element type.

The patch only adds vertex attributes so far. However, the code now
explicitly defines polygon and vertex attributes, so adding edges, loops
and tessfaces is much easier should the need arise.

Problem is that the RNA definition, which is already much more
complicated than the basic DNA/BKE definition of custom properties, now
becomes extremely bloated and cumbersome. A simpler solution would be
preferable but may not be possible within the constraints of RNA.