GRAIGNES, France (Reuters) - The lost U.S. paratrooper tapped on the door of the Rigault family’s farmhouse in Normandy in the early hours of June 6, 1944, miles south of his intended drop zone and soaking from his landing in the surrounding marshland. After four years under German occupation, 12-year-old Marthe Rigault, awoken by the roar of aircraft overhead, watched as her parents warmed the foreign soldier with a flask of coffee. By dawn, dozens of men from the 507th Parachute Infantry Regiment had hunkered down on the Rigault farm outside the village of Graignes. As they did, the distant...