fix compatibility with 0.12 firmware release.

 * The 0.12 introduces the serial number and changed the way it
   handle the serial port comunication, waiting for the \r as command
   termination instead of \n.

 * the new python API changed the way the command are sent to the device
   and how the command get submitted.

 * fixed the ogarden_cli and ogarden_gui to communicate properly with
   the new API and handle the serial number.