Bil Keane, 89, the creator of the world’s most popular single-panel newspaper comic, the Family Circus, died Tuesday. He left behind a half-century of daily visits to the Keane family where he, his wife, now-grown kids and their pets were the models for Daddy, Mommy, Billy, Dolly, Jeffy, P.J., Barfy, Sam and Kittycat. The comic…