Add function to send a custom message to headset

42 + * Version 1.0.15:
43 + * Date: 25th Apr 2013
44 + * Compatible/tested with Spokes SDK version(s): 2.8.24304.0
45 + * Changed by: Lewis Collins
46 + *   Changes:
47 + *     - Add function to send a custom message to headset
48 + *