Zynga has announced the departures of three top executives as new chief executive officer Don Mattrick continues to restructure the social gaming company. According to the Forbes.com business news website, chief operating officer David Ko, chief technology officer Cadir Lee and chief people officer Colleen McCreary are leaving the company. Mattrick said in a statement that the changes are being made in order to move senior executives closer to operations. “We are taking layers out of the executive rank to get senior leaders closer to important product initiatives,” Mattrick said. “With that in mind, I have asked the leaders to…