UdpIoPlugin

- Make the GUI do what it is supposed to (currently it is being ignored)
- add indicator of buffer status (both juce and ARM)
- Rebind to port when disconnected or prepareToPlay is called again
- Use OSC to coordinate transmission:
-- usable latency (that is initialization of readPointer in ReceiveAudioThread) can be computed based on the block sizes of both sides
-- non-fixed packet sizes
-- handle start-stop from both sides
- Add sampling rate and sample count in the packet header
- Handle dropouts appropriately (e.g.: fade out and silence for "audio", sample and hold for "sensors")
- rename NetworkSend and ReceiveAudioThread to something more meaningful