(svn r3081) -Codechange: [autoreplace] complete rewrite of autoreplace

this is a complete rewrite, that makes use of existing commands like build and sell
        this means that multiheaded train engines are replaced correctly

aircraft_cmd.c

@@ -1307,7 +1307,7 @@ static void AircraftEnterHangar(Vehicle *v)
 	ServiceAircraft(v);
 	InvalidateWindowClasses(WC_AIRCRAFT_LIST);
 
-	MaybeReplaceVehicle(v);
+	v = MaybeReplaceVehicle(v);
 
 	TriggerVehicle(v, VEHICLE_TRIGGER_DEPOT);