PrioA:
* document dns_host2ip and dns_domain2srv in Net::SIP::Dispatcher
  and make it truly asnychronous
* do not look up tcp in Dispatcher::resolve_uri  if we have no leg
  which can do tcp

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- more tests
  * invite + listen using proxy + registrar
  * call-on-hold ( c=0.0.0.0 in SDP )
  * use sdp_on_ack, asymetric_rtp in tests
  * tests using re-invites (from UAC and from UAS)
  * tests, where either the UAC or the UAS issues a BYE
  * tests with bad relay in between, which forgets
    packets, so that retransmits will be tested
  * proxy with NAT where SDP data come in
     * 18x + 2xx + INVITE
     * 2xx + ACK
  * tests for delivering packets using Net::SIP::Dispatcher:resolve_uri
  * tests for forwarding packets in stateless proxy 
    based on route, via, uri,...
  * tests for samples/ and bin/

- more documentation
  * samples for integration with other loops

- implementation
  * full support for TCP
