* SusiMail:
   - Add background mail checker, not yet enabled
   - Add idle timeout connection closer
   - Rely on idle checker for most delayed deletions
   - Cleanup resources better when shutting down session
   - Don't add deleted mails to folder, caused errors after deletions
   - Set socket soTimeouts so things don't hang forever
   - Display errors after check mail button pushed
   - More IOE debug logging