Open source IntentAndroid

Summary: Move the code to the github folder, add more docs and improve the example.

We might want to merge this with `LinkingIOS` later (it has the same functionality
plus support for deep links) but want to see how people use the `IntentAndroid`
API first (and what other methods we should add) to have more data points.

public

Reviewed By: lexs

Differential Revision: D2646936

fb-gh-sync-id: 751f35784d387efcd031f9b458821cdfde048a54

Examples/UIExplorer/UIExplorerList.android.js

@@ -38,6 +38,7 @@ var COMPONENTS = [
 var APIS = [
   require('./AccessibilityAndroidExample.android'),
   require('./BorderExample'),
+  require('./IntentAndroidExample.android'),
   require('./LayoutEventsExample'),
   require('./LayoutExample'),
   require('./PanResponderExample'),