By Daniel Kline The two fast-food giants know what the people want (bacon) but Burger King has added another all-star ingredient to its latest Whopper. For a long time — think decades — burgers came in two main varieties, with cheese or without it. Sure, you could play with basic toppings like lettuce, tomato, pickles, onions, as well as condiments like ketchup, mustard, mayo, or maybe even relish, but that’s where hamburger innovation stopped. Starting in the ’80s, fast-food chains including McDonald’s (MCD) – Get McDonald’s Corporation Report, Restaurant Brands International’s (QSR) – Get …