Question out of curiosity (a few google searches didn't explicitly answer it for me): does iOS 9 App Thinning functionality allow developers to create a single universal app across iOS, tvOS and watchOS, with the App Store being smart enough to download only the relevant modules to each device? Or does each platform require a seperate app, grouped together via Universal Purchase, and does App Thinning only remove the differences within a specific platform (e.g. binaries optimized for iPhone 5 vs 6)?