From Las Vegas Review Journal The Empire put a hit on the Mafia and buried the farm. Two years after Caesars Entertainment Corp. perplexed Wall Street by acquiring social gaming operation Playtika, the casino giant has moved past rival Zynga Inc. to the top of the business model. Social casino games are free to play on the Internet, through Facebook and other platforms. Customers have the option of paying a nominal fee — often less than $1 — to acquire thousands of gaming tokens to increase their virtual bankroll. Apparently, those pennies add up. One Wall Street analyst estimated social…