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.

Wrote radio2_test.py as a python OOK tester for new radio.so lib