JSp2Cart:

--------------------------------------------------------------------------
   Computes the Jacobian for converting from spherical to 
   cartesian coordinates. Spherical coordinates are defined as
   [r,theta,phi] where phi is the angle from the +z axis and theta
   is the angle from +x in the xy-plane.

   x = r*cos(theta)*sin(phi)
   y = r*sin(theta)*sin(phi)
   z = r*cos(phi)

   Since version 1.
--------------------------------------------------------------------------
   Form:
   jC = JSp2Cart( s )
--------------------------------------------------------------------------

   ------
   Inputs
   ------
   s	            (3,1)  Spherical coordinates [r,theta,phi]

   -------
   Outputs
   -------
   jC            (3,3)  Jacobian from spherical to cartesian
                          [ �x/�r �x/�theta �x/�phi ]
                          [ �y/�r �y/�theta �y/�phi ]
                          [ �z/�r �z/�theta �z/�phi ]

--------------------------------------------------------------------------