(svn r7523) -Feature: Add the possibility to change the newgrf configuration of a running game.

This is only possible in SP (or in the intro menu). During game play you will
 get a confirmation window when applying the changes as some actions can crash
 OpenTTD and/or make your current game unplayable.

vehicle.h

@@ -277,6 +277,7 @@ Vehicle *FindVehicleOnTileZ(TileIndex tile, byte z);
 
 void InitializeTrains(void);
 byte VehicleRandomBits(void);
+void ResetVehiclePosHash(void);
 
 bool CanFillVehicle(Vehicle *v);
 bool CanRefitTo(EngineID engine_type, CargoID cid_to);