Adjusting hex printout format for empty buffers.
Adding printout support for DS18B20 fixed<12:4> temperature readings.
Adding support for port/message types in Wireless interface.

1. Update send() and recv() member functions with port parameter.
2. Common payload limit is now 30 bytes (NRF24L01P is boundary).
3. Ripple effect on Wireless device drivers; VWI, NRF24L01P and CC1101.
4. Ripple effect on example sketches.
5. Cleanup of example sketches and debug output.