set_ambient R G B - Set the ambient color for this light.  R,
          G, and B are floating point values between 0 and 1.

	get_ambient - Get the ambient color components for this light.
          A three element list is returned with red, green and blue
          components in the first three entries.

	set_bright val - Set the brightness component of this light to
          "val", which is a floating point value between 0 and 1.

	get_bright - Return the brightness component of this light.
          The value returned is a floating point value between 0 and 1.

	set_color R G B - Set the color for this light.  R, G, and B
          are floating point values between 0 and 1.
		
	get_color - Return the color for this light.  A three element
          list is returned with red, green and blue components in the
          first three entries.

	set_position x y z w - Set the position of this light.  X, y,
          z, and w are arbitrary floating point values.  Typically,
          w=1.0. 

	get_position - Return the position for this light.  A four
          element list is returned with x, y, z, and w components in
          the first four entries.

	switch [on | off] - Determine whether or not this light is on.
          The argument has the obvious effect.