LONDON (AP) - Tens of thousands of hunters and their hounds raced through the countryside on horseback Saturday, opening a fox-hunting season that could be one of Britain's last. The more than 300 hunts had a defiant air, with participants still angry over the government's plans to ban hunting with hounds. The House of Commons voted two months ago to outlaw the sport. The House of Lords refuses to endorse the bill, but the government has threatened to force it into law anyway by next year. Fox hunting supporters were undaunted. "We are just as determined to be here next...