This is a kind of simplification/cleanup tool which joins adjacent faces and edges based on the angle.
I've written this as an exercise (since I havnt written a bmesh operator before), and because quite a few users were asking for the dissolve operator to be extended, but I think this kind of functionality needs its own operator.
access from specials menu and mesh menu.
notes
* this exposed a bug in angle_v3v3v3(). will merge fix into trunk after release.
* added utility function BM_vert_edge_angle(), to get the angle between 2 connecting edges of a vert.
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