Export config struct so it can be used in the AHRS.
Use a higher range magnetometer output format.
Reset reference magnetic vector when calibration done.
Extend hardcoded valid magnetic and acceleration magnitudes.
Export mag & acc validity flag state from AHRS.
Extend, update the messages sent to the OSD, flags, vbat and orientation.
Slowly adjust accel scale in altitude filtering.
Limit max filtered - raw barometric altitude difference.

The barometric altitude (ignoring the drift for a while) is fairly
reliable within the +/-3m error margin so make sure we don't get too far
away from it.
Read config before AHRS init.
Put config in an ealier EEPROM sector, last one seems dead.

Also set an error value guard in case it's never set by the IAP.