This allows the following pattern:
OutputDirectoryLogging.catchLogEntries()
// some initialisation code which produces log msgs,
// which will be catched and subsequently dumped to the
// logfile
Scenario sc = MySenarioUtils.createScenario();
Controler c = new Controler( sc );
c.run();
This didn't work before, because only the CollectLogMessagesAppender
created and added in the last call to ODL.catchLogEntries() was
considered when creating the logFile.
