just assume uart0 is initialized by the HAL, because it is. DRY.
also, don't ever use uart0 explicitly in example sketches, use console
and let the hal figure it out.
* BetterStream Means AP_HAL depends on AP_Common, for now, in order to have
the AVR specific pgm_char_t defined.
I'll need to factor that out in the future but for now it can stay