LOS ANGELES — Biz Markie, a hip-hop staple known for his beatboxing prowess, turntable mastery and the 1989 classic “Just a Friend,” has died. He was 57. Markie’s representative, Jenni Izumi, said the rapper-DJ died peacefully Friday evening with his wife by his side. The cause of death has not been released. “We are grateful…

Biz Markie, Known for Classic Rap Song ‘Just a Friend,’ Dies at 57