Document BVH #77
Description
We incorrectly link from https://chunky-dev.github.io/docs/reference/user_interface/render_controls/advanced/ BVH to Scene Format Octree. We need a place to describe the BVH.
https://chunky-dev.github.io/docs/reference/introduction/path_tracing/#bounding-volume-hierarchy-bvh Is probably the best place but the description is limited.
Update gramma for https://chunky-dev.github.io/docs/reference/user_interface/render_controls/advanced/ BVH SAH
"the packing of the bvh is explained in the javadocs for whatever the abstract class was called"