New York - A commercial van driven by a 77-year-old man plowed into holiday shoppers Thursday in Herald Square, killing six people and injuring five in the city's deadliest pedestrian accident in at least a decade. The rush-hour nightmare left bodies strewn on Sixth Ave. off 34th St. amid gift-wrapped packages, shattered glass and pools of blood. Four people were pronounced dead at the scene; five others were taken to St. Vincent's Manhattan Hospital and six were taken to Bellevue Hospital Center. Of those taken to Bellevue, two died, the police said. One of the victims was identified as a 15-year-old boy, Steven...