USA Today has been among publishers moving early into the mobile space, with more than a dozen properties spanning the mobile Web and apps and smartphones and tablets. As the newspaper industry grapples with the digital transition, mastering the mobile landscape will be a key part of that effort. MediaPost caught up with David Payne, SVP and chief digital officer at Gannett Co., to discuss how the company’s flagship newspaper is keeping up with the audience shift to connected devices. MP: What’s been USA Today’s approach to building out its mobile presence, especially when it comes to apps? DP: Consistently, USA Today either gets into that first wave of application development--often we’re invited into that process as new…