Blender Git Loki

Refactor: move view3dshading .blend I/O to blenkernel

Ref T76372.

Refactor: move ParticleSettings .blend I/O to IDTypeInfo callbacks

Merge remote-tracking branch 'origin/blender-v2.91-release'

Parenting: fix return value when parenting object to itself

Ensure parenting an object to itself is seen as error, by returning
`false`.

This error was introduced as part of a supposed-to-be-non-functional
cleanup rBb8d4a2aff8069dd7d6fb91ad0d9427eed489b68f.

Fix undo steps not allowing re-using old BMain in non-global undo.

Non-memfile undo steps never properly initialized the flag allowing to
re-use old Main data during undo/redo. This lead to doing a complete
full re-reading of data when undoing/redoing mode switches e.g.

Note that current undo system is supposed to support any kind of mode
switch across those steps, however this needs to be properly deeply
tested, so only comitting this to master. It would be way too risky for
2.91 release.

Fluid: Cleanup for APIC debug build setup

Fixes build issue

Cleanup: malformed doxygen sections

Docs: note the purpose of UserDef_Runtime.is_dirty

Merge branch 'blender-v2.91-release'

Merge branch 'blender-v2.91-release'

Merge branch 'blender-v2.91-release'

Merge branch 'blender-v2.91-release'

Merge remote-tracking branch 'origin/blender-v2.91-release'

Outliner: use undo-group for outliner mode switching

Switching modes no longer adds multiple undo steps
from a user perspective.

Object: use undo-group for object.switch_object

object.switch_object no longer adds multiple undo steps
from a user perspective.

Undo System: support for grouping steps with begin/end calls

This adds support for treating multiple undo steps as a single step
from the user perspective.

This is needed for outliner mode switching and `object.switch_object`
operator which change active object and mode in a single action.

Fix outliner mode toggling with multi-object pose/edit mode

For edit/pose modes clicking in the mode-column would include other
selected objects (besides the active object), causing other objects to
remain in the mode even though Control wasn't held.

Also replace `ED_object_mode_generic_exit(...)` on all objects with a
single call to `ED_object_mode_set(...)` so switching modes will only
exit the current mode, leaving objects in other modes unchanged.

Fluid: Added APIC simulation method

Basic support for velocity updates with the APIC method.

This commit adds APIC to the already existing dropdown menu for the simulation method. The APIC plugin within Mantaflow has been updated to the latest version.

Outliner: Remove "ID" from tooltip

The concept of IDs shouldn't be exposed to the user.

Cleanup: parse '--thread' as part of ARG_PASS_ENVIRONMENT

While this isn't needed at the moment, it's possible
the animation player uses the scheduler in the future.