Blender Git Loki

Merge branch 'master' into blender2.8

Fix ruler not setting line width

Cycles: Allow cancel during displacement of meshes

UI: delay tool label tip display

Displaying the labels tip immediately feels too intrusive,
make this work more like regular tooltips, displaying more quickly.

Tooltips can now uses multiple passes, each pass with it's own delay
for the next pass to show.

UI: keep showing label tooltip once it's open

This means dragging the cursor over the tools will show all labels
immediately, but only once a single label is displayed.

UI: tweak tool bar tooltips

- Only show label-tips when tools are icon-only.
- Don't show shortcuts in label-tips.
- Position both tool label & full tips around the button bounds.

Correct build errors

Cleanup: style

Join the python modules `gpu` and `_gpu` into one.

Maybe it's still early to set the new drawing api for python.
But joining these two modules is an initial step.

```
>>> gpu.
matrix
select
types
```
```
>>> gpu.types.GPU
Batch(
OffScreen(
VertBuf(
VertFormat(
```
The creation of a new offscreen object is now done by the `GPUOffscreen.__new__` method.

Reviewers: campbellbarton, dfelinto

Reviewed By: campbellbarton, dfelinto

Tags: #bf_blender_2.8

Differential Revision: https://developer.blender.org/D3667

Multi-Objects: UV_OT_follow_active_quads

Starring: the overengineered error report system to make sure only one error
is reported.

Multi-Objects: UV_OT_remove_doubles

Use kdtree for doubles (old standing TODO for this operator).

Small changes from reviewer (Dalai Felinto):
* Code style ({ is in a new line only if it is a two-line if).
* Skip objetcs loops when we know for sure nothing is selected (or all is)

https://developer.blender.org/D3441

Fix error message from MESH_OT_faces_mirror_uv

Reported/Patch by Alan Troth.

UV_OT_lightmap_pack: Distinction between edit and object modes

I don't even know why this operator was ever made to work in object mode.
That said, since it does, we should have different options for it
(or rather, always do all faces for it).

Multi-Objects: UV_OT_lightmap_pack

I removed the All Objects option. This doesn't make more sense now that
all the selected objects will be in edit mesh mode.

Cleanup: uvcalc_smart_project.py 2/2

Cleanup: uvcalc_smart_project.py

Removing old commented out code. It includes progress bar and other bits
that were never implemented for this script since the 2.5 transition.

Multi-Objects: UV_OT_smart_project

Multi-Objects: UV_OT_snap_selected

Fix T56657: Crash when creating a collection instance containing probes

Edit Mesh: Add back the option to not highlight selected faces/edges

Do note that we force showing the face dot if we are in face select mode
but faces and edges overlays are disable to not loose the selected faces
entirely.