fixes #0003262: normal vector returned by Face.normalAt(u,v) is not always a unit vector
fixes #0003262: normal vector returned by Face.normalAt(u,v) is not always a unit vector

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