#34 allow to specify IPv6 address

[Vladimir Kotal]

When IPv6 address is specified instead of FQDN, OSXnews does not
work properly.

E.g. news.belnet.be listens on both IPv4 and IPv6, but only IPv6
connection is greeted with:

simstim:~/Documents/ $ telnet news.belnet.be 119
Trying 2001:6a8:3c80::38...
Connected to ikaria.belnet.be.
Escape character is '^]'.
200 ikaria.belnet.be InterNetNews NNRP server INN 2.4.1 ready
(posting ok).
^]
telnet> q
Connection closed.

IPv4 connection is torn with:

simstim:~/Documents $ telnet 193.190.198.38 119
Trying 193.190.198.38...
Connected to ikaria.belnet.be.
Escape character is '^]'.
502 You have no permission to talk. Goodbye.
Connection closed by foreign host.

It would be nice to have the possibility to specify IPv6 address.