Update Doxyfile for the latest version of Doxygen.
Merge pull request #437 from SaberUK/insp20+doxygen-update

Update Doxyfile for the latest version of Doxygen.
m_dnsbl Fix connecting users timeouting when a dnsbl result is in the dns cache

Fixes #431 reported by @killerrabbit
Stop user initialization when the user is marked as quitting after OnSetUserIP
Either store the Resolver in DNS::AddResolverClass() or delete it before returning
Fix m_dnsbl not checking cgiirc users when the cgiirc address is elined
m_connectban Switch to OnSetUserIP hook to handle cgiirc users properly, ignore e-lined users
Remove dead code from DNS