Blender Git Loki

WIP: First compilation after change weights

This code is not tested, but as this is the first compilation without error, save this point as backup.

Cleanup: Pass `Snap Object Params * params` to` iter_snap_objects`.

And remove unnecessary `defaulf:` labels.

Fix Cycles and viewport outline mismatch due to changed sensor size.

Fix Cycles motion blur not working with CoW disabled.

Not so important but convenient for testing, and makes the Cycles tests
pass again for now.

Fix mistake in recent outliner rebuild change.

Merge branch 'master' into blender2.8

Fix assert using '//' on an unsaved file

Annoying for debug builds.

Particle edit: Fix generation of KD tree for emitters

Fixes crahs using puff brush with copy-on-write.

particle edit: Fix crash when using without copy-on-write

Particles: Fix uninitialized child orco passed to modifiers

Wrong cleanup done in 51b796ff152.

Particle edit: Need to check DONE flag from evaluated psys

Particle edit: Support children particles display with copy on write

Depsgraph: Forbid flush across scene->geometry operations

This relations is only to force geometry evaluation to happen
after scene's CoW is done. it was never meant to update geometry
when scene is being tagged.

Depsgraph: Keep track of original particle system

Allows to have quicker lookup in particle edit mode.

Particle edit: Add missing looking tag in cut brush

Particle edit: Allow children to be visible in edit mode

Follows tool settings, tested without copy-on-write.

Enabling copy-on-write still needs verification and likely some fixing.

Particle edit: Move cache update to particle batch cache implementation

The idea is to allow "regular" strands to update edit cache and hence
get the final update strands.

Draw manager: Pass object to hair batch cache

Currently unused, but is required for an upcoming work.

Particle edit: Make check to work within copy-on-write concept

Not fully optimal, we can probably store pointer to original psys
similar to ID's orig_id.

Particle edit: Edit path invalidate should trigger particle system path re-cache

Don't try to bend existing design, just follow it. It's not nice, but is
working. Just bring it back, then repeal and replace system as a whole,
making sure every bit is working according to a design.

Such quick patches only trying to make local sense of a system, defeating
it's design.