(though it's not completely feature-complete yet).
I ported over the remove doubles code from the
old bmesh branch for this, and split it into two
bmops, "Weld Verts" and "Remove Doubles".
Weld verts welds specific verts together, while remove
doubles finds doubles and welds them.
I also reverted the hotkey change I made earlier.
to bmesh. Yay! Creating faces from edge nets
is sill missing, I'm leaving that for later.
I added two new bmop functions, BMO_HeaderFlag_Buffer
and BMO_UnHeaderFlag_Buffer, which are header flag
version of BMO_Flag_Buffer and BMO_Unflag_Buffer.
The new functions properly handle setting/clearing
BM_SELECT via the selection API.
