Fixes#11435
Draft_Fillet could already handle arcs, provided they were not Draft_Arcs. The `_extract_edge` function in make_fillet.py had a strange logic, and could also return a wire which would result in problems later.
Another issue was that the `fillet` function in fillets.py did not handle the order of the edges correctly if one of the edges was an arc and the other a straight edge. The arch had to be selected first to prevent this error.
This includes `arcs`, `circle_inversion`, `circles`, `circles_apollonius`,
`circles_incomplete`, `cuboids`, `edges`, `faces`, `fillets`,
`general`, `geometry`, `intersections`, `linear_geometry`,
`offsets`, `sort_edges`, `wires`.
These are added to the `draftgeoutils` Doxygen group so that
the functions contained in each module are listed appropriately
in the automatically generated documentation.
