fix for mesh face filling when a valid edge-loop was selected but unselected connecting geometry existed inside the loop.

In this case edgenet_fill operator failed and it would fallback to filling as unordered vertices which was mostly fine but failed on some concave loops.

Add a new bmesh operator 'edgeloop_fill' fills in closed loops even if they don't make a valid edge-net.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55619 954f8c5b-7b00-dc11-b283-0030488c597c