Implement player view reflections through mirrors

[xthexder]

These will likely only need to be 1-2 bounces deep (and controlled separately from shadow maps), with the last bounce using the voxel grid data.
These are a great candidate for raytracing features to accelerate, but could be done using the previous OpenGL method, or possibly a screen / camera view texture collected on a previous frame.

This will affect gameplay, since the player needs to be able to see where they're aiming a light through a mirror.