New York Theater Ballet continues to forge ahead. Now in its thirty-ninth season, NYTB brings new ways to look at classics together with the opportunity to see work by up-and-coming choreographers. Legends & Visionaries, presented as a tribute to the late David Vaughan, dance archivist, historian and critic, began with sweetly moving remarks by NYTB company founder and artistic director, Diana Byer, Vaughan’s friend and mentee.