A few changes

Not quite sure of the protocol (and can submit a pull request for each change if it's wanted?)

In this pull request there are 3 changes, one of which is marginally more major.

1.  Shifting the hard coded node mappings and serial port to a config file, which should make it easier to have as configurable settings
2. Tweak to the readme, since nodemap uses comma separations rather than colon separators
3. Allow live data to update the status table

Thanks