Sculpt: Pose Brush Scale/Transform deform mode

This is an alternative deformation brush for the Pose Brush intended
quickly change the proportions of the mesh. The regular mode scales
using the segment's origin as a pivot. The inverted mode drags the
entire segment using the grab delta.

The only difference with the regular pose brush is that it is not
compatible with IK, so the option is disabled and set to 1 segment. The
rest of the options should work as expected.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D7374

release/scripts/startup/bl_ui/properties_paint_common.py

@@ -619,10 +619,12 @@ def brush_settings(layout, context, brush, popover=False):
 
         if brush.sculpt_tool == 'POSE':
             layout.separator()
+            layout.prop(brush, "pose_deform_type")
             layout.prop(brush, "pose_origin_type")
             layout.prop(brush, "pose_offset")
             layout.prop(brush, "pose_smooth_iterations")
-            layout.prop(brush, "pose_ik_segments")
+            if brush.pose_deform_type == 'ROTATE_TWIST':
+              layout.prop(brush, "pose_ik_segments")
             layout.prop(brush, "use_pose_ik_anchored")
             layout.separator()