In a Lower Manhattan apartment, one of the greatest living musicians and activists sat down with one of the country's newest great leaders. Pete Seeger, with a list of awards and honors longer than the neck on his famed banjo, still works tirelessly at 88 years of age. He spoke with Majora Carter, the young and indefatigable founder of Sustainable South Bronx, an organization that is re-shaping the neighborhood of her youth through pioneering green-collar economic development projects, about the environment