Qt4 bindings for avahi.

Avahi is an Implementation the DNS Service Discovery and Multicast DNS
specifications for Zeroconf Computing. It uses D-BUS for communication
between user applications and a system daemon. The daemon is used to
coordinate application efforts in caching replies, necessary to
minimize the traffic imposed on networks.

The Avahi mDNS responder is now feature complete implementing all MUSTs
and the majority of the SHOULDs of the mDNS/DNS-SD RFCs. It passes all
tests in the Apple Bonjour conformance test suite. In addition it
supports some nifty things that have never been seen elsewhere like
correct mDNS reflection across LAN segments.