DLM to share data from DerivedMesh (reduces some copying/memory allocation)
- added displistmesh_copyShared function to copy a DLM but not duplicate any
internal data
- changed crease drawing to use DerivedMesh functions... this means varying
edge width style of creases had to go, I replaced by using varying color to
show crease weight instead. Don't think this is a big loss since the subsurf
result gives you a much better indication of the crease weight anyway.
- bug fix in mirror modifier, didn't copy edge creases from editmesh correctly
8da5df8887