After Dunkin' Donuts was going to take down its legendary sign in Brighton, the question arose--what next? What are the options if you want to make sure that Dunkin' Brands Inc. doesn't put anything boring or ugly in its place? Inspired by the preservation of the Citgo sign in the 1980s, Bostonist called the Boston Landmarks Commission to see if the sign could be designated a landmark. A representative said that, to become a......