Implement broadcast functions

allow setColor, turnOn and turnOff

lifx/set/broadcast/turnOn {"color": {"css": "rgb(200, 250, 0)"}, "duration": 5000}

lifx/set/broadcast/turnOff {"duration": 5000}

lifx/set/broadcast/color {"color": {"css": "rgb(200, 250, 0)"}, "duration": 5000}