Blender Git Loki

misc changes to unterface & undo
- operator strings were doing undo pushes (in fileselector text for example), this is dumb since the operators themselves handle undo.
- interface code checks rna props are arrays rather then checking the array length.
- disable properties window pin undoing.
- sequencer refresh was calling undo, disable since this is clearnign global data not handled by undo.
- added commented out code for drawing mesh vertex index/key index, useful for debugging shapekey - hook issyes.