Sketcher Ellipse: code cleanup

deleting redundant overloaded functions involving arc-of-ellipse, a few
todo comments, not implemented methods, System(constraintlist)
constructor.

src/Mod/Sketcher/Gui/DrawSketchHandler.cpp

@@ -484,8 +484,6 @@ void DrawSketchHandler::createAutoConstraints(const std::vector<AutoConstraint>
                         geom2->getTypeId() == Part::GeomCircle::getClassTypeId() ||
                         geom2->getTypeId() == Part::GeomArcOfCircle::getClassTypeId() ) {
                         // in all these cases an intermediate element is needed
-                        // TODO: INSERT COMMON CODE HERE
-                               // in all these cases an intermediate element is needed
                         makeTangentToArcOfEllipseviaNewPoint(Obj,geom1,geom2,geoId1,geoId2);
                         return;
                     }