fixed some other UI logic in the python menu script
Added an option to use a vertex group for a reduction weight map to force reducing some areas more then others.
Mesh epydocs activeGroups can be None as well as string.
Added support for "Weighted Collapse" Before an edge could only collapse into its middle,
Now the edge collapses into a point bias'd by the 2 verts Concave/Convec "Pointyness" value as well as boundry weighting.
This works much better for boundry verts. - UV's Vcols and Weights are correctly interpolated into the new location.
Added a tool in the mesh menu for accessing the poly reduction tool.
