If we’re lucky, you and I are still talking to our best buds from childhood, riding memories of monkey bars and awkward middle school firsts into adulthood. That makes Kenan Thompson and Kel Mitchell among the luckiest. Where so many young actors flame out in a tailspin of childhood fame, not only did “Kenan and Kel” both survive All That stardom in the mid-1990s, they went on to be functional adults with colorful careers. And they’re still friends.