Add example for <NavigationTransitioner />

Summary:
Add an example for <NavigationTransitioner /> that shows how to use
<NavigationTransitioner /> and <Animated.View /> to build a stack of
animated scenes that render the navigation state.

This also defines the generic method for NavigationTransitioner to render scenes.

Reviewed By: ericvicenti

Differential Revision: D3422322

fbshipit-source-id: b9ff4c5102442a110739a546565552496349d473

Examples/UIExplorer/NavigationExperimental/NavigationExperimentalExample.js

@@ -35,6 +35,7 @@ const View = require('View');
 const EXAMPLES = {
   'CardStack + Header + Tabs Example': require('./NavigationCardStack-NavigationHeader-Tabs-example'),
   'CardStack Example': require('./NavigationCardStack-example'),
+  'Transitioner + Animated View Example': require('./NavigationTransitioner-AnimatedView-example'),
 };
 
 const EXAMPLE_STORAGE_KEY = 'NavigationExperimentalExample';