implement MAV_CMD_NAV_LOITER_TO_ALT and general mission cleanup

src/modules/navigator/navigation.h

@@ -54,21 +54,19 @@ enum NAV_CMD {
 	NAV_CMD_IDLE = 0,
 	NAV_CMD_WAYPOINT = 16,
 	NAV_CMD_LOITER_UNLIMITED = 17,
-	NAV_CMD_LOITER_TURN_COUNT = 18,
 	NAV_CMD_LOITER_TIME_LIMIT = 19,
-	NAV_CMD_RETURN_TO_LAUNCH = 20,
 	NAV_CMD_LAND = 21,
 	NAV_CMD_TAKEOFF = 22,
-	NAV_CMD_ROI = 80,
-	NAV_CMD_PATHPLANNING = 81,
+	NAV_CMD_LOITER_TO_ALT = 31,
+	NAV_CMD_DO_FOLLOW_REPOSITION = 33,
 	NAV_CMD_VTOL_TAKEOFF = 84,
 	NAV_CMD_VTOL_LAND = 85,
 	NAV_CMD_DO_JUMP = 177,
 	NAV_CMD_DO_CHANGE_SPEED = 178,
 	NAV_CMD_DO_SET_SERVO=183,
-	NAV_CMD_DO_REPEAT_SERVO=184,
-	NAV_CMD_FOLLOW_TARGET = 194, // temporary placeholder
 	NAV_CMD_DO_DIGICAM_CONTROL=203,
+	NAV_CMD_DO_MOUNT_CONFIGURE=204,
+	NAV_CMD_DO_MOUNT_CONTROL=205,
 	NAV_CMD_DO_SET_CAM_TRIGG_DIST=206,
 	NAV_CMD_DO_VTOL_TRANSITION=3000,
 	NAV_CMD_INVALID=UINT16_MAX /* ensure that casting a large number results in a specific error */
@@ -99,7 +97,8 @@ struct mission_item_s {
 	float yaw;			/**< in radians NED -PI..+PI, NAN means don't change yaw		*/
 	float loiter_radius;		/**< loiter radius in meters, 0 for a VTOL to hover     */
 	int8_t loiter_direction;	/**< 1: positive / clockwise, -1, negative.		*/
-	unsigned nav_cmd;		/**< navigation command					*/
+	bool loiter_exit_xtrack;	/**< exit xtrack location: 0 for center of loiter wp, 1 for exit location */
+	enum NAV_CMD nav_cmd;		/**< navigation command					*/
 	float acceptance_radius;	/**< default radius in which the mission is accepted as reached in meters */
 	float time_inside;		/**< time that the MAV should stay inside the radius before advancing in seconds */
 	float pitch_min;		/**< minimal pitch angle for fixed wing takeoff waypoints */