newLinearMove creates a trajectory through xyz waypoints
 
    This method works similar to newJointMove with the main
    difference being that the resulting trajectory represents
    an approximate straight line in cartesian workspace
    coordinates.
 
    NOTE:
    Because the underlying IK relies on a local optimizer, the
    generated trajectory and waypoints for large motions, 
    particularly large changes in orientation, may be poor. It 
    is important to check the output of newLinearMove() before
    sending it actual hardware.
 
    At the moment this method supports only exactly two
    waypoints per call. This method also currently only
    supports the following parameters.
 
        'Duration'  - time to completion [s]
 
    'Velocities', 'Accelerations', and 'Time' constraints are
    currently not supported.
 
    Please see the newJointMove documentation for more information.