1) If a message fails to be delivered, post a notification in the
status bar if that thread is not active and visible.
2) If a message fails to be delivered because there is no service,
keep retrying every time service becomes available again.
1) We record time sent in SMS database (date_sent).
2) We record time received in MMS database (date_received).
3) We union this information correctly in MmsSmsDatabase.
