Extend autoping timer on each stanza we receive.

Sometimes the server is too busy sending other stanzas or our connection is
saturated because of something else, so the pong arrives too late.
Prevent the autoping disconnect event by extending the timeout
each time a stanza is received.

Signed-off-by: Steffen Jaeckel <jaeckel-floss@eyet-services.de>

src/xmpp/xmpp.h

@@ -269,6 +269,8 @@ void iq_mam_request_older(ProfChatWin* win);
 void iq_register_change_password(const char* const user, const char* const password);
 void iq_muc_register_nick(const char* const roomjid);
 
+void autoping_timer_extend(void);
+
 EntityCapabilities* caps_lookup(const char* const jid);
 void caps_close(void);
 void caps_destroy(EntityCapabilities* caps);