Blender Git Loki

Cycles: Move motion triangle intersection functions to own file

Mimics how regular triangles are working and makes it more clear where
the stuff is located in the kernel.

Needed to have some forward declarations because of the current placement
of things in the kernel.

Cycles: Cleanup, better variable name

Cycles: Add utility function to fetch motion keys while on CPU side

Cycles: Cleanup, comments

Cycles: Add utility function to fetch motion triangle when on CPU side

Cycles: Cleanup, delete trailing whitespace

Fix T50460. Greying out issue with Cycles culling options.

Cycles: No need for host side memory for split kernel state buffers

Cycles: Allow mem_zero to be called on buffers without host side memory

Previous commit did this for OpenCL so only need to update CUDA

Cycles: Add OpenCL kernel for zeroing memory buffers

Transferring memory to the device was very slow and there's really no
need when only zeroing a buffer.

Cycles: Zero split kernel state memory outside of kernel

Fixes problem seen with CUDA. The global work size wasn't large enough for the
data_init kernel to zero the full buffers, so now its done from the host.

Remove unused panels (layer_passes and layer_options)

Add scene active layer

Remove scene layer and collection from context

Merge branch 'render-layers' of git.blender.org:blender into clay-engine

# Conflicts:
# source/blender/editors/space_view3d/drawobject.c

Fix compile error

Fix T50517: Rendering expecting time is negative

Merge remote-tracking branch 'origin/blender2.8' into render-layers

Review: Multithread deform code

Review: Cleanup