[Bf-committers] Patch to add a "replace" operator for vertex groups...

[Gaia]

Hi;

While setting up a mask modifier, i found myself readjusting
the mask vertex Group a few times like so:

- select missing vertices for the mask
- unselect superfluous vertices
- assign selected
- CTRL + i (to select the opposite vertices)
- remove selected
- see if mask now looks right...

I thought, it would be just nice to have a replace vertexgroup function 
instead:

- select missing vertices for the mask
- unselect superfluous vertices
- replace selected

I believe this can be useful in general.
It looks like this: http://www.pasteall.org/pic/show.php?id=52809
And here is the patch: http://www.pasteall.org/42823

So if you agree that this is an improvement, and the patch
is ok, then i can add it.

cheers,
Gaia