Remove AirBnB Native Navigation (#532)

It is no longer actively being worked on.... 
airbnb/native-navigation#114
airbnb/native-navigation#145

docs/navigation.md

@@ -9,7 +9,7 @@ This guide covers the various navigation components available in React Native. I
 
 If you're only targeting iOS, you may want to also check out [NavigatorIOS](navigation.md#navigatorios) as a way of providing a native look and feel with minimal configuration, as it provides a wrapper around the native `UINavigationController` class. This component will not work on Android, however.
 
-If you'd like to achieve a native look and feel on both iOS and Android, or you're integrating React Native into an app that already manages navigation natively, the following libraries provide native navigation on both platforms: [native-navigation](http://airbnb.io/native-navigation/), [react-native-navigation](https://github.com/wix/react-native-navigation).
+If you'd like to achieve a native look and feel on both iOS and Android, or you're integrating React Native into an app that already manages navigation natively, the following library provides native navigation on both platforms:[react-native-navigation](https://github.com/wix/react-native-navigation).
 
 ## React Navigation