Avoid NestedScrollView been required on ios

Fixes #11

Author: cesardeazevedo

index.js

@@ -1,7 +1,5 @@
 import { Platform, ScrollView } from 'react-native';
-import NestedScrollView from './lib/NestedScrollView';
 
-export default Platform.select({
-  ios: ScrollView,
-  android: NestedScrollView
-})
+export default Platform.OS === 'android'
+  ? require('./lib/NestedScrollView')
+  : ScrollView;