vehicle_control_mode.flag_armed added, reset integrals in multirotor_att_control when disarmed

src/modules/uORB/topics/vehicle_control_mode.h

@@ -64,6 +64,8 @@ struct vehicle_control_mode_s
 	uint16_t counter;   /**< incremented by the writing thread everytime new data is stored */
 	uint64_t timestamp; /**< in microseconds since system start, is set whenever the writing thread stores new data */
 
+	bool flag_armed;
+
 	bool flag_external_manual_override_ok;	/**< external override non-fatal for system. Only true for fixed wing */
 
 	// XXX needs yet to be set by state machine helper