[Part]use BSpline for makeWireString instead of Bezier curves.
[Part]use BSpline for makeWireString instead of Bezier curves.

- the bezier curves from the font definitions cause checkGeometry
  errors when extruded.  bsplines do not have this problem.

Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master