David Byrne is burning down the house on Broadway. His show “American Utopia” is a smash hit, but that isn’t the only reason the former frontman for the Talking Heads is so happy. Serena Altschul talks with Byrne about his love of performing, his growing affinity for collaboration, and his optimism, apparent in his “Reasons to Be Cheerful,” a platform that spotlights ways in which the world is getting better.