Reconnects every 2 hours

[ForNeVeR]

The experimental Horta version (see the explanation in #416) was reconnecting to the server exactly every 2 hours. It has line xmpp.timeout_ms=900000 in its config.

That's not a big problem, but it should be fixed. Current hypothesis is that it's the problem with XMPP pings (I had a similar issue in Kaiwa), and I think there was a way to tune them in Smack.

Probably we'll need to add a facility to log all XMPP messages to debug this.

Note that these reconnects seems to be completely encapsulated by Smack: the underlying application cannot see them.