This add support for rendering of the point cloud object in Blender, as a native
geometry type in Cycles that is more memory and time efficient than instancing
sphere meshes. This can be useful for rendering sand, water splashes, particles,
motion graphics, etc.
Points are currently always rendered as spheres, with backface culling. More
shapes are likely to be added later, but this is the most important one and can
be customized with shaders.
For CPU rendering the Embree primitive is used, for GPU there is our own
intersection code. Motion blur is suppored. Volumes inside points are not
currently supported.
Implemented with help from:
* Kévin Dietrich: Alembic procedural integration
* Patrick Mourse: OptiX integration
* Josh Whelchel: update for cycles-x changes
Ref T92573
Differential Revision: https://developer.blender.org/D9887
Remove prefix of filenames that is the same as the folder name. This used
to help when #includes were using individual files, but now they are always
relative to the cycles root directory and so the prefixes are redundant.
For patches and branches, git merge and rebase should be able to detect the
renames and move over code to the right file.
