Move files that have no application-specific bits (e.g. USB stack, tuning, and RF path APIs) to ../common/.
Remove dependencies on application-specific USB descriptors.
Push MAX2837 state management into rf_path_set_direction().
Adjust logic in sgpio_configure() to treat transceiver modes outside TX and RX as RX. "OFF", for example...
Allow set_transceiver_mode(OFF) to fall through the rest of the function, now that sgpio_configure() is expecting OFF as a value.
Forgot an #include in rf_path.c, from moving MAX2837 code.