* Logger class which handles actually writing logs to disk.
* Settings for logging.
* Modification to ThemeEngine to generate plaintext output for the logs as
  well. Strips trailing timestamps, as the log is timestamped itself.
* Menu action to show log directory, which is only present if logging is
  actually enabled.
* Includes alteration to RookChat patch to ensure that HTML comment timestamps
  are generated in GMT not server time, to facilitate logging with timestamps
  in local time.