After a terrible year there are signs of hope for DetroitGetty ImagesAMERICA’S carmakers appear to have returned from the grave. This week the three big ones—Ford, General Motors and Chrysler—all had good news to report. Ford recorded a wholly unexpected profit for the third quarter of nearly $1 billion, thanks in large part to a huge improvement in its North American operations. Sergio Marchionne, boss of Fiat and now Chrysler, laid out a detailed five-year plan for restoring the American compa