move source code to src folder

__tests__/App-test.tsx

@@ -4,7 +4,7 @@
 
 import 'react-native';
 import React from 'react';
-import App from '../App';
+import App from '../src/App';
 
 // Note: test renderer must be required after react-native.
 import renderer from 'react-test-renderer';

index.js

@@ -3,7 +3,7 @@
  */
 
 import {AppRegistry} from 'react-native';
-import App from './App';
+import App from './src/App';
 import {name as appName} from './app.json';
 
 Platform.OS === 'ios' ? AppRegistry.registerComponent('main', () => App) : AppRegistry.registerComponent(appName, () => App);