Bug-22: Add Word and WordStorage class

@john-hu Please help me review this patch. Thank you.
This is java 7's feature. We should use old convention because not all users upgraded to jdk7. So, please change to
```
try {
  ...
} catch (JSONException e) {
  mListener.OnError(e);
} catch (IOException e) {
  mListener.OnError(e);
}