* TODO: Add support for power-off via button and possibility disable power-off button

* TODO: create RTTY / FSK encoder for Si5351
* TODO: create RTTY / FSK encoder for Si4032
* TODO: create CW / OOK encoder -- the same one should work for both Si5351 and Si4032

* TODO: Add relevant information about RS41 hardware
* TODO: Add relevant links to other sources of information, e.g.:
  * http://happysat.nl/RS-41/RS41.html
  * https://github.com/darksidelemm/RS41HUP - 4FSK + 2FSK
  * https://github.com/darksidelemm/RS41FOX - RS41-FOX - RS41 Amateur Radio Direction Finding (Foxhunting) Beacon
  * https://github.com/bazjo/RS41_Hardware
  * https://github.com/bazjo/RS41_Decoding
  * https://destevez.net/2018/06/flashing-a-vaisala-rs41-radiosonde/
  * https://destevez.net/2017/11/tracking-an-rs41-sgp-radiosonde-and-reporting-to-aprs/
  * http://www.om3bc.com/docs/rs41/rs41_en.html