Updated readme with latest status

Updated README

Updated README with present status and new planned items

Improved message decoding. ...

Now builds a dictionary of seen devices.
Monitor FFFFFF messages removed, not needed.
Catches bad payloads and prints a warning rather than crashing.
Accepts and responds to a JOIN command.
Message and value encoders written and working.
Message and value decoders written and working.

Corrected directory path

code formatting

formatting of code

Added source files from first working tests

Added some notes about sharing low level devices

Update README.md

Initial commit