Blender Git Loki

Change 'face strength' values.

WARNING! this will break files saved with this branch and using face
strength feature (no crash or data corruption, but face strength values
will become invalid and will produce weird results)!

Rationals for this change are:
* Having strength values in natural order simplifies existing code
already, not to mention any future potential addition to strengthes.
* Now, code will work as-is, even if we decide to add more stength
values in the future.