Fix Pose Brush FK mode detecting wrong rotation origin

The Pose FK mode assings the rotation origin to the boundary of the last
visited face set in the floodfill operation. In some cases, the topology
of the model may make the flood fill operation to visit a face set as the
first one (assinging it to target) and visit it again as the last one
(assinging it to origin). This will make the pose brush to default the
origin and target to the brush location and not to the face sets as it
considers that there is only one possible boundary.
This adds a GSet to ensure that a particular face set is not visited
twice in the flood fill, fixing these cases.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D7984

Sculpt: Cloth Brush simulation area property

This makes possible to choose between a local and a global simulation
when the cloth brush is used. Local simulation is the current default.
When global simulation is enabled, the cloth brush simulates the entire
mesh without taking any simulation limits into account.

This was possible before by setting the simulation limits to 10 (the
current maximum value allowed) so the entire mesh was inside the limits,
but this was a hack as the limits scale with the radius and there should
not be any limitation on how big the simulated area can be to be able to
simulate an entire object. This also allows to make a more clear
distinction between cloth brush presets that are intended to be used in
local areas to add details or globally to generate the base shape of the
mesh.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D8481

Cleanup: Paint Cursor Refactor

The paint_draw_cursor function was handling the cursor drawing for 2D
and 3D views of all paint modes, calculating the brush radius, updating
the SculptSession data and updating and drawing all sculpt cursor
overlays for different tools. It was almost impossible to understand when
and what was being drawn and in which state the GPU matrix was.

Now everyting is organized into different functions, with clear
separation between modes, sculpt tool overlays and different drawing
setups. Update and drawing functions are also separated (this allows to
skip one PBVH query on each cursor drawing).

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D8206

Sculpt: Cloth Brush/Filter Collisions

This implements collisions in the solver of the cloth brush/filter. It
uses the scene colliders as a regular physics simulation.

There are still some parameters (friction, distance to the surface...)
that can be exposed as properties in later patches.

Thanks to Sebastian Parborg for helping me with the implementation.

Reviewed By: sergey, zeddb

Differential Revision: https://developer.blender.org/D8019

Sculpt: Sharpen Mesh Filter curvature smoothing and intensify details

This adds a curvature smoothing and intensify details properties to control
the result of the Sharpen Mesh Filter.

Curvature smoothing removes high frequency details from the precalculated
sharpen data, so the filter result has much smoother surfaces and cleaner
sharpen lines;

Intensify details displaces the vertices of creases and valleys in the direction
opposite to its neighbors average, so it intensifies high frequency details
in those areas, producing more noisy and sharp shapes:

Both this properties can be used in combination to achieve a good balance of
high and low frequency details depending on the shape and the desired result.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D8447

Fix Squash and Stretch naming in the Pose Brush deform mode

Previusly it was using the / character, which implies that there is one
deformation mode and and invert deformation mode like in the other two
deformation, but squash and stretch is only one deformation mode and
does not have an invert mode.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D8463

Sculpt: Option to lock the rotation in the Pose Brush scale deform mode

The scale deform mode includes rotation by default, so when when scaling
down a part of the models it becomes harder to control as the effect of
the rotation less predictable (similar to using trackball rotation in a
very small radius). This locks the rotation of the segment, so parts of
the model can be scaled down in a more predictable way.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D8465

Merge branch 'blender-v2.90-release'

Sculpt: Use vertices instead of faces to limit the grids in each PBVH node

This uses the vertices per grid instead of quads to set the limit of
grids per PBVH Node. This should create more leaf nodes in lower
subdivisions levels where the duplicates count is high, producing more
uniform performance across different levels.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D8454

Merge branch 'blender-v2.90-release'