ArduCopter: add static create method to AP_Rally

ArduCopter/AP_Rally.h

@@ -12,7 +12,6 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
- 
 #pragma once
 
 #include <AP_Rally/AP_Rally.h>
@@ -20,12 +19,19 @@
 
 class AP_Rally_Copter : public AP_Rally
 {
-
 public:
-    // constructor
-    AP_Rally_Copter(AP_AHRS &ahrs) : AP_Rally(ahrs) {};
+    static AP_Rally_Copter create(AP_AHRS &ahrs) {
+        return AP_Rally_Copter{ahrs};
+    }
+
+    constexpr AP_Rally_Copter(AP_Rally_Copter &&other) = default;
+
+    /* Do not allow copies */
+    AP_Rally_Copter(const AP_Rally_Copter &other) = delete;
+    AP_Rally_Copter &operator=(const AP_Rally_Copter&) = delete;
 
 private:
-    bool is_valid(const Location &rally_point) const override;
+    AP_Rally_Copter(AP_AHRS &ahrs) : AP_Rally(ahrs) { }
 
+    bool is_valid(const Location &rally_point) const override;
 };