My implementation of AS_AT_LEAST_IOS9 broke when 8.4.1 was released.
I ran the iOS 9.0 simulator to find the proper `kCFCoreFoundationVersionNumber` value for iOS9, added this as `kCFCoreFoundationVersionNumber_iOS_9_0` and updated the `AS_AT_LEAST_IOS9` macro
Initial open-source release of ASMultiplexImageNode. Documentation and
example code forthcoming.
Note: ASMultiplexImageNode requires Xcode 6 to compile. Tests are now
compiled against the iOS 8 SDK and run on iOS 7.1 and iOS 8.