(svn r2962) - const correctness for all Get* functions and most Draw* functions that don't change their pointer parameters

- change a lot of byte player types to PlayerID
- beautify header files, same "#endif /* filename */" ending

vehicle_gui.h

@@ -7,7 +7,7 @@
 
 struct vehiclelist_d;
 
-void DrawVehicleProfitButton(Vehicle *v, int x, int y);
+void DrawVehicleProfitButton(const Vehicle *v, int x, int y);
 CargoID DrawVehicleRefitWindow(const Vehicle *v, int sel);
 void InitializeVehiclesGuiList(void);