The new Chevrolet Aveo RS concept debuting at the Detroit auto show reveals that GM has something smart and small in the works ready to meet Ford’s much-ballyhooed new Fiestasubcompact.Larger than the current Aveo and donning what Chevy calls a “European hot-hatch look,” the five-door “Borocay Blue” RS show car is intended to appeal to the youth market—or any market, really. It previews the