Zinio, a company focused in digital publishing tech, has just released Zinio Reader 4, an Adobe AIR application that enables access to thousands of magazines — interactive magazines too, and National Geographic celebrates with a freebie. Zinio Reader 4 allows users to instantly access over 2,000 magazines by utilizing Adobe’s AIR framework. It is essentially a cloud-based digital library that will be synced to your devices. Users who install this application can pay once for a digital copy of a magazine, and it will instantly be available to the user for reading in its entirety on any platform…