[Vysper] stanza receiving and relaying

[Matus Zamborsky]

I read rfc 3920 and 3921 and I understand the routing behind presence, 
messages and iqs. I also read the code of StanzaRelay and 
StanzaReceiver, but I could not find the difference between routing 
presence, messages and iqs. Is there something I dont see, or this part 
of Vysper is not fully written?