There are a few places where DerivedMesh is still used, most notably
when calling the (not yet ported) cloth simulation. There is also still
the use of Object.derivedDeform and Object.derivedFinal. Those places are
marked with a TODO.
Some functions in the editors module were copied to accept Mesh. Those
already had 'mesh' in the name; the copies are suffixed with '__real_mesh'
for easy renaming later when the DM-based functionality is removed.
