(Reuters) - Mobile game developer Zynga Inc topped Wall Street estimates for quarterly bookings on Wednesday, riding on the success of its new titles "Merge Magic!" and "Game of Thrones Slots Casino".The company reported bookings of $433 million for the fourth quarter ended Dec. 31, beating average analysts' estimate of $418.8 million, according to IBES data from Refinitiv.Bookings indicate future revenue including sales of virtual goods, such as currency and lives, within the games.The..