Update multiprocessing_logging.py

[shellster]

trafficstars

Please don't merge without careful review.

• Removed old Python 2 stuff because I don't need it and it is very old by now.
• Fixed the error
• Added a signal handler that makes sure that close() gets called on exit so all log messages get printed.

[jruere]

@shellster I'm not willing to discard Python 2 support. I consider this module for Python 2 with support for Python 3.

If you need only Python 3, I recommend a new module leveraging the new things in the standard library. There is already support for multiprocessing there but it must be setup and it's not trivial. A module to do it simply will be used by many, I think.

I'll recommend this new module from this current module if it looks good. :)

[jruere]

The problem was solved more simply in #58.