"Having vowed never to record again, one of pop's most lauded singer-songwriters, Joni Mitchell, is returning with a new album this year. A tribute album is also due for release and Radio 2 was recently granted a rare interview. Is this the resurfacing of just another rock relic or that rare event: a comeback worth waiting for? Not one to shy away from controversy, our Joni. "To enjoy my music, you need depth and emotionality," she recently told one interviewer. "Those two ........"