[DEBUG] Proactive mode as a default

 If connection mode is not specified in config file, error occurs.
 Now, it sets proactive mode as a default connection mode, when
mode is omitted in config file.
[DEBUG] Proactive mode as default parameter, logging level config

 - Configuring proactive mode as a default parameter, and it is
  moved from parse_config to the top.

 - Changed default logging level to logging.INFO and it is
  configurable through config file.

 - Remove the config dumping to log to prevent password leak
Removed commented unused codes
Merge pull request #11 from kyuhojeong/master

[DEBUG] Proactive mode as a default