Log Message:
Update to 1.56:

1.56  Mon Nov 15 21:00:00 CET 2010
    - When sending messages in text mode, now we wait a bit
      between the +CMSG command and the actual text.
      Fixes RT #61729. Thanks to Boris Ivanov for the report.
    - Added clear example of logging to a custom file
    - Added a warning for not implemented _read_messages_text()
    - Added a "assume_registered" option to skip GSM network
      registration on buggy/problematic devices.