By RAF CASERT, JOHN LEICESTER and ELAINE GANLEY, Associated Press OMAHA BEACH, France (AP) — Standing on the windswept beaches and bluffs of Normandy, a dwindling number of aging veterans of history's greatest air and sea invasion received the thanks and praise of a world transformed by their sacrifice. The mission now, they said, was to honor the dead and keep their memory alive, 75 years after the