The irony of watching “12 Years a Slave” the night before embarking on a little tour of Charleston, S.C., was not lost on me. Nor was the fact that William Tecumseh Sherman is one of my great, great, great uncles, a fact that I may or may not have proudly shouted from one of the city’s many church steeples had I imbibed enough bourbon. But this was more of a food and architecture tour of that lovely city.