Blender Git Loki

Merge branch 'master' into blender2.8

Cleanup: rename gizmo access functions

Add float in API names since we may want access to other types.

Cleanup: trailing space

Fix T56457: Crash when selecting Grease Pencil objects

Thanks to Charlie Jolly (@charlie) for the backtrace

Depsgraph: Add query methods to identify all the ID's that a given datablock depends on

This commit adds a new method, DEG_foreach_ancestor_ID()
to accompany the existing DEG_foreach_descendent_ID().

It can be used to help print/collect all the ID's that
a given ID block depends on (i.e. all the datablocks that
need to be evaluated before the datablock of interest can
be evaluated)

Cleanup: Fix variable shadowing

Cleanup: Fix typos

fixed some crashes regarding automatic cache reallocation

Remove MESH_OT_drop_named_image

This was never ported to work with Cycles, so it is basically useless in 2.8.
It can always be brought back in the future.

Multi-Objects: MESH_OT_colors_reverse

Fix missing color management in Cycles viewport on macOS.

The half float extension is not supported on macOS, rather it's simply
part of OpenGL core so we don't need to check.

decouple FM motion data cache from pointcache

the FM stores validity and motiondata in its meshislands, the point cache only holds the objects.

Fix relationship lines selectable

Object constraint lines viewport drawing

The core logic of this implementation comes from the drawobject.c from 2.7x.
I'm using `ts.colorGridAxisZ` for its color because of the legacy code:

```
UI_GetThemeColor3ubv(TH_GRID, col1);
UI_make_axis_color(col1, col2, 'Z');
glColor3ubv(col2);
```

There is nothing stopping us from adding this to the theme though, as it should
have been the case to start with.

Workspaces: remove separate workspaces.blend config file.

This is quite confusing in the current UI, with both startup.blend and
workspaces.blend containing a list of workspaces. In practice you'd usually
want to save workspaces to both files.

The downside of having a single file may be that you then can't disable
certain workspaces by default, but we could add a setting for that.

Workspaces: add new default workspaces in startup.blend.

Workspaces: replace bundled workspace.blend with embedded startup.blend.

We want these to have the same workspaces in both, so there is no reason
to have two files that are identical.

Fix outliner crash loading some .blend files without treestore.

Fix system workspaces.blend not being found on some systems.

Viewport: add default set of HDRI images.

These are taken from HDRI Haven (https://hdrihaven.com). Many thanks to
Greg Zaal for creating and releasing them under a CC0 license!

The HDRIs are intended to be used in the Lookdev display mode. With
1K resolution and compression they are not intended for final renders,
but it keeps the file size small and the difference is not noticeable
for lighting.

Command used for compression:
oiiotool %s --ch R,G,B -d float --compression dwab:300 -o output/%s