Fix endless logging & collect early log messages in the log file

[jscheidtmann]

There was a bug in Multiproclogging that could lead to an endless loop:

• logger.handle() was called for elements in the queue
• which lead to an additional entry in the queue.

This is now fixed, by removing all handlers in the logging process and then creating a filehandler for writing to the logfile.

[jscheidtmann]

You will probably see me requesting more changes to the log system after I return from vacation. :-D