Hard-rocking renaissance man Jon Langford tears it up. Photo courtesy Bloodshot Records. In a fairer, better world, Jon Langford would need no introduction; in a world that makes Kenny Chesney a country star, he probably does. (Unless, of course, you read our interview with Langford last fall.) So: Since founding the protean punk outfit the Mekons in Leeds, England, three decades or so ago, he’s become that Godfather of the Chicago alt-country scene that…