MS_ROT3 - Elasticity matrix rotation.

Rotates an elasticity matrix around the three axes.

Usage:
    [CR] = MS_rot3(C,alp,bet,gam)
        C: input 6x6 elasticity matrix
        alp: clockwise rotation about 1-axis, looking at origin
        bet: clockwise rotation about 2-axis, looking at origin
        gam: clockwise rotation about 3-axis, looking at origin

[CR] = MS_rot3(...,'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:
    Angles are given in degrees and correspond to yaw, -dip and aximuth,
    respectvly. The rotations are applied in order, ie: alpha, then beta
    then gamma (by default). The variables C, alp, bet and gam can be
    arrays or scalars but (1) the angles must all be the
    same length and (2) either C or all the angles must be scalars unless
    they are the same length.