Blender Git Loki

Add a hair system to particles to eventually replace the current pathcaches.

Modifier copy function uses const now.

Remove the simple hair guide generator, can test through the API now.

Merge branch 'blender2.8' into hair_guides

Merge branch 'blender2.8' into hair_guides

Fix indexing of vertex buffers for Cycles hair.

Render support for hair systems in Cycles.

Also cache guide tangents and normals and fiber root positions in export data.

New HairExportCache struct to unify pre-computation of hair data for OpenGL, render, and eventual data export.

Cycles: split off particle data gathering into separate function.

The general particle caching "Obtain" functions can be used for any
curve-type data in objects, including the new hair system data.

Fix changed signature of applyModifier callback.

Merge branch 'blender2.8' into hair_guides

Add new modifier callbacks for switching from DerivedMesh.

Merge branch 'blender2.8' into hair_guides

Depsgraph update after changing guide curves through the fur modifier.

Make sure hair follicle binding is updated before using invalid indices in drawing.

Merge branch 'blender2.8' into hair_guides

Test API in the fur modifier for creating custom guide curves with python.

The fur modifier is just a testbed for the underlying hair system.
The API is intended to allow specifying guide curves with python scripts
without having to worry about inconsistent state. All curves are first
defined in a python-friendly way, then applied to the hair system in one step.

Alternative guide curve setter function that works better for RNA.

Move guide curve into a nested struct, so it can be replace in one operation.