PlanetRot:

--------------------------------------------------------------------------
   Transform from ECI to planet-fixed axes.
   The Earth, Mars, and the moon have high-fidelity functions.
   Other bodies use Seidelmann, The Explanatory Supplement to the Astronomical
   Almanac.

   Since version 7.
--------------------------------------------------------------------------
   Form:
   b = PlanetRot( planet, jD )
--------------------------------------------------------------------------

   ------
   Inputs
   ------
   planet    (:)    String name of planet
   jD       (1,1)   Julian date

   -------
   Outputs
   -------
   b        (3,3)   Rotation matrix from ECI to planet fixed frame

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