Persistent state storage

[pwarren]

It'd be nice to have the last used menu settings come back when the radio's turned on, with a way to reset it too I guess.

I'd imagine we'd need a menu state struct, which can be written to FLASH memory at some interval, maybe a second or so after a change?

[MichaelRColton]

Agreed. Depending on what power state we drop down into, we may be able to preserve those things in memory without too much of a hit to standby current.