Expose additional private modules

Summary: - TextInputState as TextInput.State
- Touchable
- flattenStyle as StyleSheet.flatten
- ReactNativeART as ART

Original discussion in #1821
Closes https://github.com/facebook/react-native/pull/3308

Reviewed By: sebmarkbage

Differential Revision: D2527152

Pulled By: javache

fb-gh-sync-id: 19d4ef9d4c0e6587b9f0793e1ca624aebb034f3b

Libraries/Components/TextInput/TextInput.js

@@ -86,6 +86,11 @@ type Event = Object;
  * ```
  */
 var TextInput = React.createClass({
+  statics: {
+    /* TODO(brentvatne) docs are needed for this */
+    State: TextInputState,
+  },
+
   propTypes: {
     /**
      * Can tell TextInput to automatically capitalize certain characters.