-------------------------------------------------------------------------------
   Converts R and V to a, e, rP and rA.
-------------------------------------------------------------------------------
   Form:
   [a, e, rP, rA] = RV2AE( r, v, mu )
-------------------------------------------------------------------------------

   ------
   Inputs
   ------
   r               (3,:) Position vector
   v               (3,:) Velocity vector
   mu                    Gravitational constant

   -------
   Outputs
   -------
   a               (1,:) Semi-major axis
   e               (1,:) Eccentricity
   rP              (1,:) Perigee
   rA              (1,:) Apogee

-------------------------------------------------------------------------------
	  References:	  Bate, R.R., et. al. Fundamentals of Astrodynamics, pp. 70-71.
-------------------------------------------------------------------------------