Uses Rodrigues's formula to create a 3x3 rotation matrix R. The results of R*xMatrix is x rotated theta degrees about u. INPUTS u - axis of rotation theta - angle of rotation (radians) OUTPUTS R - 3x3 Rotation matrix EXAMPLE R = rotation_matrix3D( [0 0 1], pi/4 ) R * [1 0 0]' DATESTAMP 29-Sep-2005 2:00pm See also RECOVER_ROTATION3D, ROTATION_MATRIX2D