---------------------------------------------------------------------------
   Mach number from mass flow parameter. You need to enter a guess for
   the Mach number since any mass flow parameter has two possible Mach
   numbers. The initial guess must be on the same side of 1 as the
   expected Mach Number.

   This routine uses a Newton-Raphson method to find the Mach number.
---------------------------------------------------------------------------
   Form:
   machNo = MachFromMassFlowParameter( gamma, r, mFP, m0, units )
---------------------------------------------------------------------------

   ------
   Inputs
   ------
   gamma      (1,1)   Rate of specific heats
   r          (1,1)   Gas constant
   mFP        (1,:)   Mass flow parameter
   m0         (1,:)   Initial guess
   units      (1,:)   'eng' or 'mks'

   -------
   Outputs
   -------
   machNo     (1,:)   Mach number

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