fix(location): Add a method to convert magnetic to true north

ladybug/location.py

@@ -197,6 +197,9 @@ def is_default(self):
         """Get a boolean for whether the Location properties are defaulted."""
         return self.latitude == 0 and self.longitude == 0 and self.elevation == 0
 
+    def magnetic_to_true_north(self, magnetic_north=0):
+        pass
+
     def duplicate(self):
         """Duplicate location."""
         return self.__copy__()