Add support for Zeroconf (Bonjour/Avahi) service discovery

[jodal]

Some MPD clients support autodetection of MPD servers through the use of Zeroconf.

To connect to the open source Avahi implemenation of Zeroconf, we need to add python-dbus as a dependency. python-dbus is also required for the MPRIS frontend. An example in Python showing how to publish a service for automatic discovery through Avahi can be found at http://avahi.org/wiki/PythonPublishExample

[jodal]

We probably want to put this on hold till after we've moved to PyGI, since libavahi can be used through PyGI. Adding support for Avahi before moving to PyGI would add to the work required by that migration.

[txomon]

Why has been this closed?

[jodal]

@adamcik closed a bunch of issues that are far from our top priorities. If it is an important feature, the request will resurface. If not, we won't hear anything, and it's less noise in the issue tracker.

That said, I can imagine that I'll be adding Zeroconf myself sometime after the PyGI conversion.

[adamcik]

Basically this is trying to increase focus, as is the vision doc by reducing the number of ideas we are "actively" pursuing at once. I also have a use case for re-adding this at one point, but for now far out wishlist items that can/should be extensions have been closed.

[jodal]

Zeroconf service discovery is supported as of commit d723db8.