MS_ROTM - Create a cartesian rotation matrix.

[ M ] = MS_rotM( alp, bet, gam )

Inputs:
   alp - clockwise about 1-axis (looking at origin, == yaw)
   bet - clockwise about 2-axis (looking at origin, == -dip)
   gam - clockwise about 3-axis (looking at origin, == azimuth)
         angles are in ** degrees **, they should be scalars.

Output: is M, a 3x3 rotation matrix

[M] = MS_rotM(...,'order',V)
    order: V is a 3 element vector containing the order in which to apply the 3 rotations.
           Default is [1 2 3].

Notes:
  The rotations are applied in order, ie: alpha, then beta then gamma (by default).