Small fixes for Python 3

inner_times now correctly set on both interfaces. ...

Tested in simulation

Now passes and uses inner_times override to radio driver ...

MIHO008 white_light working in simulation
and the ENER002 still uses the older inner_times=8

radio_config now making it through to OnAir.TwoBitInterface.send()

Rationalised all comment styles. ...

The double hash (##) is reserved for commented out lines of code.
The single hash (#) is reserved for normal comments.

Moved setup code from global scope of Registry to energenie.init() ...

This makes it possible to use the registry in test cases

Refactored usages of raw message to use Message() ...

Removed all usages of showMessage, alterMessage

Improved separation of test harness messages

Major tidy up of test harness and lifecycle methods

Commissioned a tx path for MiHome adaptor Plus. ...

This is a temporary path, but it generates the correct message

LegacyDevice tx path commissioned end to end

Most of the OnAir interface coded or spec'ed now

Implementation checklist added for OnAir

Method signatures defined for OnAir adaptors

Spec'ed out responsibilities of OnAir interfaces

Placeholder added to architecture for radio interface adaptors