- the resulting selection is now correct
internal details
- bev_rebuild_polygon() now only rebuilds polygons that are attached to a bevel vertex (was rebuilding ALL).
... need to take care we don't leave faces pointing to removed geometry, so far this works fine.
- bev_rebuild_polygon() uses stack memory for <32 size ngons to reduce allocs.
- skip hash lookup when removing bevel verts (use tag instead).