[Draft] Cleaned code in arc 3Points preview
[Draft] Cleaned code in arc 3Points preview

Arc tracker during creation is computed by arc tracker new method.
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