[Hgengine-devs] Culling

[Josh <axl...@gm...>]

I think I have gotten frustum culling working again.
We are using a bounding box with a preliminary sphere test.
I need to figure out how to build hierarchical bounding boxes with the 
nodes.

I also added in an occlusion test too, which seems pretty quick in the 
worst case scenario of no occluders.
That should obviously used if you render some large occluders first.

Josh