Removed threaded dns (it might make a comeback some day, but as it stands its incompa...

Removed threaded dns (it might make a comeback some day, but as it stands its incompatible with the new OO resolver)
Migrated to new OO resolver, removed as much firedns craq as is safe to do so, operates over one file descriptor now and keyed against request id.
The only way to use the system is via class Resolver (so i'll need to migrate the rest of the ircd to use it)

git-svn-id: http://svn.inspircd.org/repository/trunk/inspircd@4622 e03df62e-2008-0410-955e-edbf42e46eb7