Fixed handling initial radio state parameter.
Changed ChannelSenseRequest to be a message because it's not a network packet.
Added error handling and default value for default bitrate in DetailedRadio.
Changed enum to be public.
Deleted unused control messages.

Deleted RECEPTION_STARTED, SYNC_SUCCESS, SYNC_FAILURE, RADIO_SWITCHING_OVER.
BTW, these were not real control messages in the sense of they did not
directly control any state in their destination. If anything then these
should have been signals but for now we are going to live without them.