Blender Git Loki

Fix merge errors

Merge branch 'blender2.8' into greasepencil-object

Fix for edit modes (sculpt, weight paint) menus not showing in header

But introduced on 2b0f02057f457acec1ed9444ee7d833ab26d0d33

Some minor cleanup.

Use static assert in Clay engine to ensure struct alignment

WIP: Add a cache system for strokes

The new cache is allocated to save the strokes and is only recalculated when there are changes.

Need more testing to be sure all situations are working fine.

Startup.blend: set EEVEE as the default engine

The original idea was to use Clay as the default. But since clay may not
even be in the final release, we can't afford to have a startup.blend
that doesn't deliver a reliable result regardless of build options.

Fix T51449: empty node editor continuously redrawing and using CPU.

Mesh Center: improved center-of-mass calculation

Previous method was based on face-area, giving un-even results
based on topology and gave issues with zero area faces.

This method gives matching results for concave ngons and the same geometry triangulated.

Fix again DwM bbones drawing.

Stupid mistake in rB6824ee0595c9dd7d1c18864f2 fix, again reported by
@campbellbarton, thanks.

UI: Add template_search (version of template_ID for non-IDs)

Adds a version of template_ID that can be used for non-ID properties.
The property to search for and the collection to search in has to be
passed to it.
Like template_ID it also takes arguments to define a 'new' and 'unlink'
operator. They will be displayed as icon-only buttons then.
Also added a version that can display preview thumbnails.

Had to do some additional changes to make text-buttons support
displaying/modifying empty RNA properties.

This will be needed for workspaces, see D2451.

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D2666

Cleanup: Rename field

Merge branch 'blender2.8' into greasepencil-object

Cleanup: Extract pixel scale function

Merge branch 'blender2.8' into greasepencil-object

Merge branch 'blender2.8' into greasepencil-object

Use different points for stroke ends calculation

With old method the end of the stroke sometimes looked weird

Increase thickness limit range

Remove static matrix definition

Fix UI panel error