Costco may have a catalyst on the horizon...Costco Wholesale Corp (COST -0.84%) has proven itself to be a winner for both shoppers -- helping them to save money -- and investors -- helping them to make money -- over time. The company is known for its $1.50 hotdogs,$5 rotisserie chicken, and a wide variety of grocery and general merchandise sold for rock bottom prices. Costco's earnings have soared into the billions of dollars, and the stock price has followed, advancing about 180% over the past five years. ...