AP_BattMonitor: fixed example build
AP_NavEKF: fixed return of offset in getVariances()
AP_GPS: cope with different MON-HW message size in u-Blox Neo7
RC_Channel: added static functions to simplify operations on all channels

this avoids vehicle code having to loop over all channels for common
operations
Plane: use new channel output API
Rover: use new channel output API
Copter: enable passthrough auxillary channels
Plane: fixed some warnings
Plane: build fix