LineArt: Fix merge conflicts.

LineArt: Smoothing chains before angle splitting.

LineArt: In-front UI hints.

LineArt: Floating edge type.

Merge remote-tracking branch 'origin/master' into temp-lineart-contained

Merge remote-tracking branch 'origin/master' into temp-lineart-contained

Documentation: Replace the bgl API in the gpu module exemples

Fix accidental lines removed in the last commit

Python GPU: Add reference of PyObject GPU object to the GPU object itself

Instead of creating different python wrappers for the same GPU object,
return the same `PyObject` created earlier.

This also allows for more secure access to existing GPU objects.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D11044

Fix gross errors in previous commit

Cleanup: compiler warnings

Fix T85470: Simple deform modifier causes artifacts at low angles

The formula used to compute the bend did subtraction of two big numbers
to get the position. Changed to find the delta and add that,
by rearranging the formula into a more numerically stable form.

Reviewed By: mano-wii, campbellbarton

Ref D11074

Python GPU: Add new methods to port the code templates in the manual

This commit adds a new API tha allow to replace the bgl API in the exemples on:
https://docs.blender.org/api/current/gpu.html

**Overview (New API):**
```
gpu.state: active_framebuffer_get
GPUFramebuffer: read_color
GPUOffscreen: texture_color
```

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D11031

BLI: add a common base class for Map iterators

This is useful for an upcoming commit that allows removing
an element based on an iterator.

Revert "Fix crash running constraint, modifier, fx from missing NULL check"

This reverts commit f4d5a69cf8512aafcc697d1b09f65489015b6af4.

This causes bpy.ops.object.modifier_apply.poll() to fail as
well as modifier binding operators (breaking tests).

LineArt: Occlusion effectiveness in material.

LineArt: UI For occlusion effectiveness.

LineArt: Ignore triangle when it's ineffective.

Cleanup: Rename `#if GPU_USE_PY_REFERENCES` to `#ifndef GPU_NO_USE_PY_REFERENCES`

This is safer for incremental build.

And there was already a macro `GPU_USE_PY_REFERENCES` used elsewhere.

Fix/Workaround T87511: snap gizmo flickers on Ctrl-Drag

Hack to bypass drag events, eventually the gizmo API
should support this use case without hacks.