This is still the same contour as before, as UFO spec allows both;
it's just normalized so that the first segments' off-curves appear at
the bottom, and the first point in the contour is an on-curve.
I copied the ReverseContourPointPen from the robofab.pens. I think it's useful for the Cu2QuPen to
have a `reverse_direction` argument which inverts the contours' winding direction. I didn't want to
add a dependency on robofab, since things are in transitions... We will add it to the future "penBox"
package (or whatever it'll be called) once that is set up.
