Previously, curves sculpt tools only worked on original data. This was
very limiting, because one could effectively only sculpt the curves when
all procedural effects were turned off. This patch adds support for curves
sculpting while looking the result of procedural effects (like deformation
based on the surface mesh). This functionality is also known as "crazy space"
support in Blender.
For more details see D15407.
Differential Revision: https://developer.blender.org/D15407
