Improved configurability of message repeat patterns. ...

Tested with different repeat lengths.
Optimum seems to be 8 inner, 1 outer transmits

Tested with learning mode. ...

Works with all 4 switch patterns.
Can now independently switch 4 switches.
Some occasional RF reliability problems that need measuring.

Improved flow of code, specifically radio_transmit() ...

Pushes previous mode and restores at end of transmit.
This should auto-return to standby or receive as appropriate.
This will make it easier to implement mode hopping schemes later.

Simulation gets further now due to gpio_sim detection

radio_rpi.so now built as part of the pi build process ...

legacy.py now uses the prebuilt radio_rpi.so

Tested radio2.py on Raspberry Pi, now works with OOK transmit

radio2.py ctypes wrapper ready for testing

Preparations for new radio interface added to the architecture