Implement Face-Based Occlusion

[Valkryst]

We want to treat the subject's face as a 2D mesh. Depending on the face's position, that mesh may cover (occlude) parts of the earrings and necklace as if they existed in the real world.

This is a more advanced technique than the previous, earring-only, rotation-based occlusion removed in commit badc6369b88dc29a5353b3d37f58e4182bb7a61f.