Andrew Maclean authored Oct 11, 2016 and Michael Fogleman committed Oct 17, 2016

Bill Lorenson noticed that the front face of orientable surfaces was being
 displayed as a back face. This arose as a "hack" when these functions
 were
  first implemented because the cross-product used to create the normals
  was
   right-handed, thus the triangulation orientation was clockwise.
    Additionally there were weird triangulations in the
    ParametricSuperEllipsoid
     and ParametricSuperToroid.

     The following three fixes have been applied:

     1) The orientation of the normals is fixed in the case of
     anti-clockwise
        ordering by calculating cross(Dv,Du) instead of cross(Du,Dv).
	   When this is done the normals point in the expected direction
	   and the
	      front face is rendered correctly. See:
	      vtkParametricFunctionSource.cxx.
	      2) All the surfaces now implement anti-clockwise ordering
	      with respect to the
	         triangulation.
		 3) The ParametricSuperEllipsoid and ParametricSuperToroid
		 have been reworked,
		    now the surface is constructed as four pieces that are
		    abutted together,
		       this removes the triangulations resulting in weird
		       appearances.
		       4) In order to implement the anti-clockwise
		       ordering in the triangulation
		          the x, y points have had to be swapped in a few
			  cases.
			  5) TestParametricFunctions.png has had to be
			  replaced. The images for
			     ParametricTorus, ParametricSuperEllipsoid and
			     ParametricSuperToroid
			        changed as a result of the above changes