[avahi] Adding a GtkTreeView to avahi-browse

[Peter Onion]

I'm tidying up some additions I made to avahi-browse that add a
gtkTreeView to display the available services. I intend to offer it for
inclusion in either the examples or utils  directories.

I've got it all working so now I'm trying to get it to build as part of
the normal make process....

I've added an extra test in configure.ac to test for libglade but when
I run aclocal it complains about "AM_CHECK_PYMOD" not being found and
autoconf fails with the message  "error: possibly undefined macro:
AM_CHECK_PYMOD"

Although I use the auto tools in a very simple way for my own projects
I'm still a beginner when it comes to a setup as complex as avahi so I
don't know how to fix this.  Can anyone help me please ?

Peter