Blender Git Loki

- Save MDISPS layer when applying modifier.
All sculpting used to disappear before. Save MDISPS if new mesh has got the same faces amount.
NOTE: maybe some other layers should be saved?
- Apply multires modififier if MDISPS was auto-created.
Multires's applyModifier used to return unchanged DM when MDISPS was auto-created.
- Set multires totlvl from MDISPS layer when new multires was added to mesh with existing MDISPS layer.