AP_NavEKF: Added public function to get NED position
AP_NavEKF: Added gyro bias variance scale for on-ground
AP_NavEKF: bug fixes for height fusion and covariance initialisation
Plane : Additional NavEKF flash logging
AP_NavEKF : Additional flash logging
Plane : EKF data logging fixes
AP_NavEKF : remove debug code
AP_NavEKF : remove onGround airspeed detect bug
AP_NavEKF : improved On Ground check
Plane : Updated NavEKF flash data logging
AP_NavEKF: brought some tuning parameters out to header
AP_NavEKF: Added height rate adaptive wind speed process noise
AP_NavEKF: make it possible for NavEKF to be a AHRS member

ready for AHRS integration
AP_AHRS: create AP_AHRS_NavEKF class

subclass of AP_AHRS_DCM, just a wrapper for now, will add EKF calls
next
Plane: use AP_AHRS_NavEKF when available
AP_AHRS: allow NavEKF to be enabled at runtime with AHRS_EKF_USE=1
AP_NavEKF: implemented getRotationBodyToNED()
GCS_MAVLink: rename EKF message to AHRS2
GCS_MAVLink: update from upstream
AP_NavEKF: don't report altitude yet, and removed debug code