This fixes below bugs:

* addReply() had used native compare operator for string ids
  => descendants may appears at wrong position
* CONTEXT_FETCH_SUCCESS had added the focused status as the reply of the *first* status in ancestors, not last status.
  => descendants may also appears wrong position as well as correct position
* TIMELINE_UPDATE had added the status to replies of *itself* instead of replied status
  => browser will hangs if you open the status due to a circular reference