I've gone with 'None' for when there's no data, rather than {}. That
makes for simpler checks on if there is data (a dict.get('foo') only
checks for that, not the dict structure otherwise).
If no 'suit' in the data we assume no Odyssey, but otherwise plough on
with dict.get() statements as they'll default to None if it's not
present.
*Users* of this monitor.state[] extra data get to choose what to do if
some data is present but not other.
Also refactors data.py to edmc_data.py as I'm having weird issues with
PyCharm debugger not starting, and this seems to be to do with module
name clashes.
