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

More design on the tx/rx and air_interface pipeline

Renamed encoder as TwoBit, as it encodes two bits per byte. ...

This is the encoding protocol used with legacy OOK devices

Started to plan out the tx/rx pipeline for payloads and message buffers

Initial design of a message Router

Capabilities of devices turned into flags, with query method in base class

Mock registry store created, auto_create is working

Documented requirement for a simple persistent data store for the Registry

Started to implement device classes code. ...

Simple mocking interface now working.

Method signatures for Registry sketched out

Initial design for enhanced persistent registry done

Some ideas about device registration added

Method signatures for device classes added

Started to flesh out device classes proposed interfaces

Python 3 now supported. ...

Logger now stores apparent power and real power headings.
Logger now stores temperature from eTRV in csv file

factored out python2/3 differences on raw_input

Updated device database comments for MIHO002 device

Now displays receive time of incoming messages

Corrected incorrect comment in switch.py

Noted the layering of switching between tx/rx might be sub optimal

Fine tuned settings when sharing MiHome and legacy devices

OOK(legacy) and FSK(MiHome) working in same combined.py build

Wrote a sample combined.py to use MiHome and legacy together. ...

Not yet tested

Renamed new radio2 module as radio, and removed old code

Removed any remaining spi-direct and tidied the build process. ...

Tested monitor.py, switch.py and legacy.py on Raspberry Pi.
All work from the same driver now.

Removed legacy direct-to-SPI interface. ...

This code now does FSK tx/rx and OOK tx from the same driver.

Tested FSK tx and rx on Pi, works fine ...

Tested both monitor.py and switch.py