Blender Git Loki

Further split of the object derived mesh update into mesh vs. editmesh operations.

Mesh and editmesh are calculated in separate functions. In order to get to a point
where splitting into individual modifiers makes sense, the first step is to have
two separate operations for these.

Note that changing edit mode does not rebuild the depsgraph, so we cannot selectively
add only one or the other at build time. Instead both operations are added, but only
one of them is actually executed. Currently this uses an internal test for the edit
mesh, but could later be controlled on the depsgraph level based on active branches.