The way we were getting diff to apply to vcos from target object was just bad!
Also, fixed another related issue - negated scale would be clamped to nearly zero,
now only consider absolute version of size (we do not care about its sign here anyway).
This should be backported to 2.74 (with previous commit too).
The issue was actually affecting all data types that are not regular CDLayer ones, since by default
DerivedMesh references mesh data (verts, edges, etc. - modifying custom normals often implies
modifying edges' sarpness too).
Modfying edge/face sharpness etc. could directly affect the mesh in this case, **bad**!
So we detect whether we are copying data types that may affect non-CDlayers data, and whether
verts array of org dm is same as mesh one - in which case we copy the DM. This avoids
useless copying in most cases.
Note Edit Normals was quite obviously suffering the same issue.
Error in custom split normals work, non-autosmooth normals != vertex normals!
Loops from flat faces shall take normal of their face, not their vertex.
Tsst...
Nothing much to say here, basic tool to make normals point toward a target,
or to make them point 'outward' as if object was a spheroid (useful for game bushes etc.).
Also, forgot a big thank you to Campbell for the extensive review work he has done on this project!
