Testcases for auto-url linking in comments:

http://www.nucleuscms.org/ should be linked
www.nucleuscms.org should be linked
Previous sentence.www.nucleuscms.org should be linked
Previous sentence.http://www.nucleuscms.org should be linked
awww... that hurts. Should not be linked
http://ftp.nucleuscms.org/ should NOT be an FTP link
ftp://www.nucleuscms.org/ should be linked as FTP
ftp.nucleuscms.org should be linked
Previous sentence.ftp.nucleuscms.org should be linked
Previous sentence.ftp://ftp.nucleuscms.org should be linked
naftp.ha should not be linked
mailto:someone@example.org -> Linked
someone@example.org -> not linked
http://www.example.org/?foo=x&bar=y => ampersand entity ok?
<<<http://www.blaat.com>>> => < & > should not be included in link
&http://www.blaat.com&& => neither should &
https://www.bla.com/
https://bla.com/
<a href="http://help.blogger.com/bin/answer.py?answer=698&topic=36">blogger help</a> => should become <a href="http://...">blogger help</a>
https://www.bla.com/, => the comma should not be linked