Base refactor 2/4

Include extra legacy values in ObjectBase struct

Missing Base to be ObjectBase convertion for mesh join operator

Base refactor 4/4

Rebase ObjectBase > Base

Remove any reference to scene->base from the old viewport code

This allows non-clay engine to see the objects as well, even if their code will be dropped later

Base refactor 1/4

Rename Base.flag > Base.flag_legacy

Base refactor 3/4

Rename Base > BaseLegacy

Note manual changes on:
* deg_builder_nodes.h
* rna_object.c
* KX_Light.cpp

Rna is still using Base directly for the ObjectBaseLegacy rna object.
Depsgraph change will be removed later.

Merge branch 'blender2.8' into render-layers

Merge remote-tracking branch 'origin/blender2.8' into render-layers

Merge remote-tracking branch 'origin/clay-engine' into render-layers

Build Clay engine by default

Another fixup for rB6cdb3845 (Added collection props getter/setter)

Values were getting clamped

Merge remote-tracking branch 'origin/clay-engine' into render-layers

UI: use the "USE" flag for collection settings

Note, this should be a proper uiTemplate, but a pure python approach seems to work fine for now

RNA: macros to wrap collection settings use

Update collection engine setings when updating collection values

Placeholder for depsgraph evaluation of collection engine settings

layer: getter/setter for USE flag

Fix bplayer (c)

RNA: use new getter/setter functions for LayerEngineSettings

Fixup for rB6cdb3845 (Added collection props getter/setter)