OceanTV: Check status of controller before starting broadcast (#114)

[ao-david]

createBroadcastAndRequestHardware now makes a call to getDeviceStatus for the controller to ensure that the controller will even respond to hardware start events before trying to create a new broadcast. This will give a pretty good indicator that the controller is not powered, likely due to a low power event on the rig.

[ao-david]

The check now fires a controllerFailureEvent which is handled by both the hardware state machine (transition back to hardware off) and the broadcast state machine (transitions back to idle or slate and calls onfailureclosure)

[saxon-milton]

closes #114