By DOMINIC PRINCE As good as it gets: Dunmore Town on Harbour Island is a slice of Caribbean peace and quietThe Bahamas has a long colonial tradition. Over the years it has attracted numerous Britons and a fair smattering of superstars. Model Elle Macpherson is a regular, as are actor Johnny Depp and naughty boy golfer Tiger Woods.More soberly, the Duke of Windsor was its governor from 1940 to