Blender Git Loki

Shading: Extend Vector Math Node with Sin, Cos, Tan and Wrap functions

This adds some extra functions recently added to the float Maths Node.
Not all functions have been ported over in this patch.

Also:
+ Tidy up menu
+ Change node color to match other vector nodes, this helps distinguish vector and float nodes in the tree
+ Move shared OSL functions to new header node_math.h

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D6713

GPencil: Change default z-depth offset to 0.150

Merge branch 'master' into greasepencil-object

GPencil: Fix On/OFF buttons for VFX

As the VFX was using if the mode was render, and this mode was shared with the shading type, the Viewport ON/OFF button was not working as expected.

Now, the VFX use a is_viewport control and the is_render is not used.

GPencil: Change Weight Paint to Blend values

Before, to substract weights it was necessary to press Ctrl key, but now the weight paint work equals to mesh weight paint blending weights and the Ctrl key is not used anymore.

This also allows to define the target weight easily.

Fix property warning due to recent commit

```Warning: property 'mode' not found in keymap item 'TRANSFORM_OT_bbone_resize'```

GPencil: Add rotation effect to Blur and change default value

build_environment: Upgraded Embree to 3.8.0

The latest versions of Embree allow similar motion interpolation
as Cycles' own BVH.

undoexp: add message when having to actually re-allocate ID during undo.

Merge branch 'undo-experiments' into undo-experiments-swap-reread-datablocks

Conflicts:
source/blender/blenloader/intern/readfile.c

properly use 'unique ID allocation' when reading new ID in undo case.

Merge branch 'id-ensure-unique-memory-address' into undo-experiments

Factorize unique ID mem address allocation into a util functions.

GPencil: Rename some params in Material panel

GPencil: New Rotation parameter for Blur VFX

Still pending (only var added)

GPencil: Change Loop option for Onion Skin

Now is Show Start Frame

DRW: Fix viewport render always rendering with transparent background

GPencil: Fix Duotone Colorize error in Panel

The props were using old BITONE name mode.

GPencil: Convert Blur size to float and avoid unedeed passes if size is 0

Fix small typo in BGL API docs

Differential Revision: https://developer.blender.org/D6681