Blender Git Loki

Cleanup: trailing space

Merge branch 'master' into blender2.8

Cleanup: replace comment headings w/ doxy groups

Also minor changes:

- Remove unused headers.
- rename SimpleExprParseState -> ExprParseState
- rename max_ops -> ops_count_alloc

Was misleading since maximums are often limits which can't be exceeded.

Cleanup: missed when using doxy groups

Multi-Objects: Initial select similar support

Note: I had to add an epsilon on top of the threshould for SIMVERT_NORMAL.
Otherwise I was getting differences such as 0.000000something when comparing
supposed-to-be-identical normals.

The way I see it, the Threshold option is a user feature, where users can
control more or less what they want selected. While the epsilon is a
non-negotiable requirement for our float comparison here.

This includes support for:
* SIMVERT_NORMAL
* SIMVERT_FACE
* SIMVERT_EDGE

Not included and currently not supported/disabled:
* SIMVERT_VGROUP
* SIMEDGE_*
* SIMFACE_*

While we are working on this, we prevent users from using the non-ported modes.
Note: the bmo_similar.c file is still around, to be removed in the near future.

Everyone: Please fell free to jump in and help tackling the missing modes.

For details on the implementation discussion:
https://developer.blender.org/D3674

Move select similar to its own file

Cleanup: BLI_expr_pylike argument ordering

- Order array length after the array.
- Put return argument last.

Cleanup: rename BLI_simple_expr -> BLI_expr_pylike_eval

Simple isn't a good prefix for library names since
lots of unrelated modules could be called 'simple'.

Include 'py' in module name since this is a subset of Python,
one of the main motivations for this is to be Python like/compatible.

Cleanup: style

Correct invalid enum default

Cleanup: remove dummy tooltips

UV Snap: minor uv-nearest optimizations

- Pass in the snap distance
(to avoid comparisons in the multi-object version).
- Loop directly over BMLoop's (without using the iterator).
- Use squared distance instead of manhattan.

Fix T56827: Crash when enable onion skin in multiwindow

The problem was the cache was not set as dirty if one of the window had the overlay disabled.

GP: Remove vertex transformation when mode is not EDIT mode

GP: Change Frames title for Onion panel

GP: change hide icon in materials

LookDev: Use theme background instead of world color

This is much less confusing than relying on an hidden parameter (the world
color) that you can only see if you disable the world node tree.

Eevee: Rename "Trace Quality" into "Trace Precision"

The thing is that the quality is something a bit subjective regarding this
option value.

A more precise trace will have more noise so quality is also diminished in
a way. I believe that using "Precision" is more correct than "Quality" in
this case.

LookDev: Use black background color if world is not present

StudioLight: Fix crash when closing blender

The studiolight was being free after the window manager and was attempting
to stop the job again.