Bill Withers' songs run through our memories: "Ain't No Sunshine," "Lean on Me," "Use Me," "Grandma's Hands." Learning there was a new documentary about him, I wondered how long ago he died. The answer is, he still lives and survives as a happy man. "Still Bill" is about a man who topped the charts, walked away from it all in 1985 and is pleased that he did. He didn't burn out....