Made getRealExternalStorageDirectory static and public and changed the dataPath location to use Android standards

@arturoc This a small update to my previous patch

1. Made getRealExternalStorageDirectory static and public.
This way you can use this method in your application as well if needed.

2. Changed the dataPath location to the proper storage location.
According to the official developer guide, files written to the external storage should be placed in: /Android/data/<package_name>

More information can be found in the Android guide: http://developer.android.com/guide/topics/data/data-storage.html#filesExternal section Accessing files on external storage

This will also help to keep the SDcard clean and prevents assets from being indexed as /Android/data usually contains a .nomedia file.