Add ability to link multiple pre-comps to a single Camera layer
PROBLEM: If you have multiple pre-comps with 3D layers that need to be resolved within their individual pre-comps and then continuosly rasterized within your main comp, the only way to have them all share the same 3D space is to copy the 3D camera into each pre-comp, or link each camera to a single null in the main comp.
SOLUTION: Allow users to define a single 3D camera layer from any comp and have it dynamically link so that all pre-comps referencing that camera will move within a shared 3D space
