The 'edge fill' code failed on filling tiny small polygons. It has a limit
check for double points, which was hardcoded set to 0.0003.
That is (commented in code too) a weak part. Better would be to define a
bounding box first, and then derive the limit from that.
Further, the edge fill code uses blender EditEdge data, which fails when
the filling code removes edges. Certainly a topic to work on once, this
code is from the 80ies!
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