Initial Logbook read and write

simdata/include/gate.h

@@ -35,12 +35,12 @@ namespace germanairlinesva_simdata
 
     public:
       // From X-Plane or MakeRwys
-      Gate(const std::string &designator,
+      Gate(std::string designator,
            double latitude,
            double longitude,
            std::uint8_t radius);
       // From database
-      Gate(const std::string &designator,
+      Gate(std::string designator,
            germanairlinesva_geodata::point center,
            std::uint8_t radius);