(Note: Posse members Mike and Libby Gagne recently visited John Lewis' new barbecue joint. This is Mike's report from that visit.) Charleston, South Carolina has long been a culinary destination showcasing some of the most American of cuisines. Lewis Barbecue, the eponymous BBQ haven for Texas pit master John Lewis opened just a few months back and has caught the attention of many along the eastern seaboard. Given the Posse's past with John and the mark he left at places like Franklin, John Mueller BBQ, and La Barbecue, being only an hour away from our beach vacation spot seemed too…