Blender Git Loki

Depsgraph: Add command line argument to debug UUIDs

Will trigger code paths which makes sure UUIDs are generated and
are unique.

Enabled with --debug-depsgraph-uuid (which is also implied by
--debug-depsgraph).

Sequencer: Add session UUID check function

Is aimed for use during development and debug, to help
verifying that operations do not leave sequences with
invalid UUIDs.

Sequencer: Add session UUID to Sequence

This is the first step for having sequences covered with session UUID
with the goal to remove code which uses original sequence pointer to
match sequences.

Currently this UUID is maintained on file load, allocation and leaf
duplication function.There are more cases to cover and ensure UUID
is re-generated or re-used when needed. It will be done as follow-up
development.

Depsgraph: Use explicit flag that ID is to copied for copy-on-write

Before this this situation was deducted using NO_MAIN flag, which is
no really reliable.

This new flags makes things explicit. Currently unused, but will be
used by the new code, and will replace legacy checks eventually.

Sequencer: Add session UUID field to the Sequence

Initial implementation of generic session UUID API

Add generic session UUID structures to DNA

Allows to use pre-defined structure for session UUIDs in all data
structures which needs it: pose channels, sequencer strips, modifiers.

The goal of all this is to have a reliable way of matching original
and copy-on-written versions of data, so that it's possible to
preserve runtime caches.

Relabeled sub-panels under 'Viewport Display' in fluid properties
- Relabeled 'Color Mapping' to 'Grid Display'
- Relabeled 'Debug Velocity' to 'Vector Display'

Fluid: Added option to control the scaling of display vectors with their magnitudes

Merge branch 'master' into soc-2020-info-editor

Outliner: Fix crash opening scenes view

The collection enable box should only show in scenes view.

Custom Menus : merge

Custom Menus : fix pie menu buttons

Cleanup: Add TODO comments

Merge branch 'master' into soc-2020-outliner

Merge branch 'master' into property-search-ui-v2

Added Particle system class and Tests to extend the framework

GPencil: Fix SVG export problem for active frame

If the current frame was higher, the export was not done.

More light tree volume tweaks

Merge remote-tracking branch 'origin/soc-2020-info-editor' into soc-2020-info-editor