[spambayes-dev] a bit better received header parsing

[Skip Montanaro]

A few days ago Tim noticed that some ip addresses in Received: headers were
being broken down in the wrong order.  For example, '[199.249.165.175]'
would yield fragments in the wrong order: '[199.249.165.175]',
'249.165.175]', '165.175]' and '175]'.  The problem was that the hostname
recognizer was catching them and fragmenting them from right-to-left, as if
they were hostnames.

I solved that problem and a couple others related to locating hostnames and
ip addresses in Received: headers.  I have no idea if it will help or not,
but your database will be oh-so-much-cleaner if you do a complete retrain
after a cvs up.

Cheers,

Skip