The D.C. food cart landscape is slowly but surely changing from a sea of hot dogs and half-smokes to a kaleidescope of world flavors. Hungry residents can now munch on the likes of bulgogi, schwarma, jerk chicken, and tacos. Taco carts are a particularly important addition because they appear to solve not one but two problems currently plaguing the District: lack of good street food and lack of good Mexican food. Moreover, tacos are an…