fix for bug with edge-slide doing UV correction when the faces connected to one of the sliding edges dont have contiguous UV's (or vcols etc).
resolve by using faces adjacent to the ones directly connected to the edge that sliding.

This isnt a prefect solution but it resolves the common case where an edge slides along a UV seam.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56366 954f8c5b-7b00-dc11-b283-0030488c597c