Merge remote-tracking branch 'upstream/master' into ArduCopter-3.2

Conflicts:
	ArduCopter/APM_Config.h
	ArduCopter/ArduCopter.pde
	ArduCopter/GCS_Mavlink.pde
	ArduCopter/Parameters.h
	ArduCopter/ReleaseNotes.txt
	ArduCopter/config.h
	ArduCopter/control_auto.pde
	ArduCopter/control_rtl.pde
	ArduCopter/ekf_check.pde
	libraries/AP_Compass/Compass.cpp
	libraries/AP_InertialSensor/AP_InertialSensor.cpp
	libraries/AP_NavEKF/AP_NavEKF.cpp