Projection Node

[boberfly]

Currently the solution for a projection is to use a DCC tool to create a second UVset. I think it might be better to just have a ProjectionTextureNode which can input a projection matrix/camera directly in, way less memory storing multiple unique UVsets.

This could be a really cool node for some workflows involving projections, especially if we can one day get HdBlackbird running into Nuke...