Sale of gas-guzzling brand falls through
                                
                                
                                    (Newser) -
                                    The once-mighty Hummer is going away for good. GM has begun winding down the brand after a sale to a Chinese company fell through. It's the second brand, along with Saturn, that GM has failed to sell as part of its restructuring. Only about 2,500 Hummers remain in stock,...