By Daniel Kline The fast-food chain leans on its signature sandwich for menu innovation. Burger King has come pretty loose with using its iconic Whopper name. As long as a burger uses the basic construction of the famous sandwich, the Restaurant Brands International (QSR) – Get Restaurant Brands International Inc Report company seems willing to deem it a Whopper. That makes sense — calling something the Halloween Whopper of the Arbor Dy Whopper gives it instant credibility. The chain, however, seems willing to put just about anything on top of two hamburgers sandwiched between two sesame seed…