* Retains ability to read from Analog Pin
* Adds ability to read RSSI from PWM channel value as is done in OpenLRSng, EazyUHF, and various other LRS.
* Handles any type of RSSI that provides RSSI values inverted - i.e. when the low value is the best signal and the high value is the worst signal.
* Has different key names from all existing RSSI parameters to provide for a clean break and easier distinguishing.
* Existing parameters are marked as obsolete
- abstracted verify_command so that command-wide actions can happen more cleanly, namely mission_item_reached
- This also brings the structure in line with plane and rover
Randy Mackay
Robert Lefebvre
Stewart Loving-Gibbard
Jonathan Challinger
Tom Pittenger
Peter Barker
Andrew Tridgell