Plane: check both ground and airspeed in autocal test

when the airspeed ratio is far too low we were not raising it as the
airspeed was never getting above the minimum airspeed

Pair-Programmed-With: Jon Challinger
INS: check for good calibration for 10seconds

Shortened gyro calibration commit also halved the total time we would
look for a good gyro calibration.  This restores the total time to 10
seconds.
HAL_AVR: fixed build
Copter: add inav vs baro arming check

In-flight Barometer sanity checking will be a more complete solution but
until then this should catch some bad pre-flight barometer behaviour
Copter: lean angle arming check
Param doc typo
Copter: motorsync cli test
AP_AHRS & AP_Math: fixed bug in use of AHRS_TRIM parameters
Rover: typo in mode stearing should be steering
HAL_PX4: enable the FMU PWM pins to be used as GPIO when needed
AP_BoardConfig: board specific config library

used to control board specific parameters, such as PWM output count
Rover: enable AP_BoardConfig
Copter: enable AP_BoardConfig
Plane: enable AP_BoardConfig
AP_Relay: enable up to 4 relay pins
AP_Camera: updates for relay API change
Plane: fixed relay handling

the parameters were badly out of whack!
Plane: fixed servo and relay repeat code
Rover: fixes for AP_Relay API change
Copter: fixes for AP_Relay API change