Gunther Schuller, on of America’s most accomplished contemporary classical and jazz musicians, died Sunday morning in Boston. He was 89. Schuller was highly productive and influential as a composer, conductor, educator, author and music producer throughout his impressive career. He was a close friend and collaborator of such giants as Miles Davis and Frank Zappa, but his musical interests have spanned a much wider range of genres than most of his contemporaries. "The thing that may make me unique is that I have simultaneously had seven full-time careers in music over the last 50 or 60 years,” Schuller said. “That's more than Leonard Bernstein." Schuller grew up in New York City, where his father served as a violinist in the New York Philharmonic