Blender Git Loki

Cleanup: Refactor proximity node to be more data type agnostic

Before, distances from each component were handled in the same loop,
making it more complicated to add support for more component types
in the future (and probably hurting performance by dealing with two
BVH trees at the same time, though I didn't test that).

Now each component is handled in a separate function, so that adding
support for another component type is much simpler.