A design studio founded by a longtime slot machine industry veteran has been acquired by social gaming giant Zynga, which is seeking an avenue into Nevada’s gaming market. San Francisco-based Zynga, developer of “Farmville,” “Words With Friends,” and other freeplay social games, did not disclose a purchase price for Spooky Cool Labs. The 40-person game studio, which is based in Chicago, focuses on developing social casino games. Spooky Cool Labs was founded by veteran slot machine designer Joe Kaminkow, who spent more than a two decades with International Game Technology, developing some of the casino industry’s best performing slot machine…