Started refactoring

Pre-factoring work done prior to pushing more code into the C domain.

Tweaked payload format further. ...

Reset all devices and re-learnt the house code
Can now switch all devices on and off, together, and independently.
legacy.py test code now demonstrates this in a loop

Added a test mode to test all 16 patterns of legacy control messages. ...

Run legacy.py and try numbers 0 to F in learning mode.
In theory you should be able to select 4 different switch addresses
plus an 'all addresses', but I can't get this to work on my 7 plugs,
they all respond as switch number 1 regardless of what code I send
in learning mode.

Attempts to get multiple device addresses working. ...

Seems to be a discrepancy between documentation and sample C code.
Stopping here until I get this clarified.

Fixed legacy import errors

Renamed modulator as encoder

7 legacy adaptors now turning on and off with this trimmed code

Got old code working again. ...

Looks like the extra bytes inserted by the buffer bug actually make it work.
This is probably related to sync bytes

Tweaks to legacy learn feature

Rewrote legacy.py to use new modulation code. ...

Not yet tested on a real Raspberry Pi

Slight improvements to timing of message transmission. ...

Still seem to get 'failed to send repeated payload to HRF' after a while
Suspect the FIFO is filling up or something.

legacy OOK test harness is working. ...

Note that sometimes we get 'Failed to send repeated payload to HRF'

Implemented a standalone switch exerciser demo. ...

Note this only really works with Adaptor Plus
(unless you seed the directory with your device id's first)

Started work on OOK support. ...

Ported C code into radio.py
Split out monitor and switch. Monitor.py is now just a monitor.
Switch.py needs more work to make it just a switch.
legacy.py will be a demo app for legacy (green button) devices.