gre.move_layer(
    layer_name,
    dx,
    dy,
    x,
    y
)
            Move a layer to a new position.  The layer_name is the name of the layer
                        or a variable that is associated with the layer name. Setting dx
                        or dy  will move the layer by the specified delta from its current
                        position.  The  dx and dy values can be 0 to set an
                        absolute position using the
                        x and y values only.
Parameters:
        layer_name  The model full path of the layer to move
        dx          A delta from the current x position or 0 to move using x
        dy          A delta from the current y position or 0 to move using y
        x           The x position to move to in absolute co-ordinates (omit to use dx)
        y           The y position to move to in absolute co-ordinates (omit to use dy)