Fox Networks has updated its Fox Now app for iOS and Apple TV, adding shows from FX and National Geographic in addition to the normal set of Fox content. Available in the U.S., the Fox Now app requires that users already subscribe to an existing pay-TV service, and provides access to up to 500 hours of content across the network’s brands, including current episodes and seasons. The separate FXNow and Nat Geo apps will still be available. Fox…