Rover: replace location_offset() and get_distance() function calls with Location object member function calls

This allows removing duplicated code

APMrover2/GCS_Mavlink.cpp

@@ -810,19 +810,19 @@ void GCS_MAVLINK_Rover::handleMessage(mavlink_message_t* msg)
                     const float ne_x = packet.x * rover.ahrs.cos_yaw() - packet.y * rover.ahrs.sin_yaw();
                     const float ne_y = packet.x * rover.ahrs.sin_yaw() + packet.y * rover.ahrs.cos_yaw();
                     // add offset to current location
-                    location_offset(target_loc, ne_x, ne_y);
+                    target_loc.offset(ne_x, ne_y);
                     }
                     break;
 
                 case MAV_FRAME_LOCAL_OFFSET_NED:
                     // add offset to current location
-                    location_offset(target_loc, packet.x, packet.y);
+                    target_loc.offset(packet.x, packet.y);
                     break;
 
                 default:
                     // MAV_FRAME_LOCAL_NED interpret as an offset from home
                     target_loc = rover.ahrs.get_home();
-                    location_offset(target_loc, packet.x, packet.y);
+                    target_loc.offset(packet.x, packet.y);
                     break;
                 }
             }

APMrover2/commands.cpp

@@ -71,7 +71,7 @@ void Rover::update_home()
     barometer.update_calibration();
 
     if (ahrs.home_is_set() &&
-        get_distance(loc, ahrs.get_home()) < DISTANCE_HOME_MINCHANGE) {
+        loc.get_distance(ahrs.get_home()) < DISTANCE_HOME_MINCHANGE) {
         // insufficiently moved from current home - don't change it
         return;
     }

APMrover2/mode.cpp

@@ -199,7 +199,7 @@ void Mode::set_desired_location(const struct Location& destination, float next_l
     _destination = destination;
 
     // initialise distance
-    _distance_to_destination = get_distance(_origin, _destination);
+    _distance_to_destination = _origin.get_distance(_destination);
     _reached_destination = false;
 
     // set final desired speed
@@ -231,7 +231,7 @@ bool Mode::set_desired_location_NED(const Vector3f& destination, float next_leg_
         return false;
     }
     // apply offset
-    location_offset(destination_ned, destination.x, destination.y);
+    destination_ned.offset(destination.x, destination.y);
     set_desired_location(destination_ned, next_leg_bearing_cd);
     return true;
 }
@@ -552,7 +552,7 @@ void Mode::calc_stopping_location(Location& stopping_loc)
     // calculate stopping position from current location in meters
     const Vector2f stopping_offset = velocity.normalized() * stopping_dist;
 
-    location_offset(stopping_loc, stopping_offset.x, stopping_offset.y);
+    stopping_loc.offset(stopping_offset.x, stopping_offset.y);
 }
 
 Mode *Rover::mode_from_mode_num(const enum Mode::Number num)

APMrover2/mode_auto.cpp

@@ -36,7 +36,7 @@ void ModeAuto::update()
     switch (_submode) {
         case Auto_WP:
         {
-            _distance_to_destination = get_distance(rover.current_loc, _destination);
+            _distance_to_destination = rover.current_loc.get_distance(_destination);
             const bool near_wp = _distance_to_destination <= rover.g.waypoint_radius;
             // check if we've reached the destination
             if (!_reached_destination && (near_wp || location_passed_point(rover.current_loc, _origin, _destination))) {

APMrover2/mode_guided.cpp

@@ -18,7 +18,7 @@ void ModeGuided::update()
     switch (_guided_mode) {
         case Guided_WP:
         {
-            _distance_to_destination = get_distance(rover.current_loc, _destination);
+            _distance_to_destination = rover.current_loc.get_distance(_destination);
             const bool near_wp = _distance_to_destination <= rover.g.waypoint_radius;
             // check if we've reached the destination
             if (!_reached_destination && (near_wp || location_passed_point(rover.current_loc, _origin, _destination))) {

APMrover2/mode_loiter.cpp

@@ -21,7 +21,7 @@ bool ModeLoiter::_enter()
 void ModeLoiter::update()
 {
     // get distance (in meters) to destination
-    _distance_to_destination = get_distance(rover.current_loc, _destination);
+    _distance_to_destination = rover.current_loc.get_distance(_destination);
 
     // if within loiter radius slew desired speed towards zero and use existing desired heading
     if (_distance_to_destination <= g2.loit_radius) {

APMrover2/mode_rtl.cpp

@@ -25,7 +25,7 @@ bool ModeRTL::_enter()
 void ModeRTL::update()
 {
     // calculate distance to home
-    _distance_to_destination = get_distance(rover.current_loc, _destination);
+    _distance_to_destination = rover.current_loc.get_distance(_destination);
     const bool near_wp = _distance_to_destination <= rover.g.waypoint_radius;
     // check if we've reached the destination
     if (!_reached_destination && (near_wp || location_passed_point(rover.current_loc, _origin, _destination))) {

APMrover2/mode_smart_rtl.cpp

@@ -59,7 +59,7 @@ void ModeSmartRTL::update()
                 }
             }
             // check if we've reached the next point
-            _distance_to_destination = get_distance(rover.current_loc, _destination);
+            _distance_to_destination = rover.current_loc.get_distance(_destination);
             if (_distance_to_destination <= rover.g.waypoint_radius || location_passed_point(rover.current_loc, _origin, _destination)) {
                 _load_point = true;
             }