Lululemon: Costco ripped off our leggings

Lululemon is suing Costco over the wholesale retailer's athletic-wear, which it claims is confusingly similar to its "path-breaking" leggings, jackets and sweatshirts. According to the lawsuit, filed Friday in the U.S. District Court for the Central District of California [PDF], these items violate trademark law because "some customers incorrectly belie…