Spamitarium changes

[Matthias Andree]

Hi Jonathan,

I have committed the version with two changes:
- I have bumped the version to 0.5.1
- I have added your authorship to the AUTHORS section again (Feel free
to edit the range of years, it's 2004 - 2009 for Tom's parts of the
code, and ...-2017 for yours).

Please grab the changes from here (a web browser is fine if you don't
want to use SVN) and include them in the next submission.
https://svn.code.sf.net/p/bogofilter/code/trunk/bogofilter/contrib/

Thanks again!

Regards,
Matthias