Blender Git Loki

Cleanup: Use more const qualifiers

Merge branch 'master' into blender2.8

Task scheduler: Optimize parallel loop over lists

The goal is to address performance regression when going from
few threads to 10s of threads. On a systems with more than 32
CPU threads the benefit of threaded loop was actually harmful.

There are following tweaks now:

- The chunk size is adaptive for the number of threads, which
minimizes scheduling overhead.

- The number of tasks is adaptive to the list size and chunk
size.

Here comes performance comparison on the production shot:

Number of threads DEG time before DEG time after
44 0.09 0.02
32 0.055 0.025
16 0.025 0.025
8 0.035 0.033

Comment out all derived mesh evaluation

Seems all the usecases of derived mesh are if-defed already,
so no need to have API for it in place, and definitely no
need to waste CPU ticks on converting evaluated mesh to
derived mesh.

Depsgraph: Don't use derived mesh

Ideally would need to make check based on evaluated mesh,
but is now a good time to go away from derived mesh.

Modifier stack: Only ensure derived mesh when USE_DERIVEDMESH is defined

This is more an internal transition away from derived mesh.

Modifier stack: Use evaluated mesh to check normals

Vertex parent: Remove CCGDM optimization

Currently we never return CCGDM from the modifier stack,
so the optimization was doing pretty much nothing.

Removing it completely for now, it needs to be re-done
with the new evaluated Mesh/Subdiv.

UI: increase spacing at sides of headers, to avoid region split zone overlap.

Fis T57948: Crash in 2.8x lookdev

Fix T57891: Radius of strip hair doesn't scale with object scale

Note that this only works fine with uniformly scaled objects.
Otherwise, the hair thickness will vary in a weird way depending on viewing
angles.

Images: "Image" submenu in "Add" menu

The submenu has two entries currently: "Reference" and "Background".
Both operators produce an image empty with different settings.

Add option not to print debug/info in ngon_tessellate.

That func can be called a lot, generating a lot of noise in the
console...

GP: Fix bottom statistics

Tool System: define tools for lattice editmode

Fix error generating toolbar tooltip

C code needed to be updated for module move.

Merge branch 'master' into blender2.8

Removed superfluous NULL check

Merge branch 'master' into blender2.8

Multires: Cleanup, remove unused function