Basic implementation for a sorter that can return an array of pointers to MessageQueueItems which puts the unused items at the back and leaves the rest in order
pulled initialization away from the constructor so the object can be reinitialized
Using the message queue sorter
thinking about a protocol
Let a channel consist of a sender and a receiver, not just a receiver
added defaults for BaseSenderReceiver  methods return values
Removed redundant include in RFMessageControl.cpp
Added an example which uses the MiniRPC library to control the led in the
BigDomeButton
Copy item into the callback, makes it more clear that the item is only valid within the scope of the callback