AvahiPublisher: Made it run standalone

This still needs some love, i.e. some undefined local members (max_retries).
Pylint gives a poor score.  But this version seems to run sufficiently well
for now.
Added a very simple HTTP Keyserver

This does not speak HKP, nor is it any fancy.
In fact, it is not even a "key" server. It just server any data
you tell it via HTTP GET.
Keyserver: Made it use a higher port if the one is in use

Also introduced logging.  We probably need to deal with the blocking
call, somehow.
keyserver: Replaced KEYDATA with keydata from the argument

Now it actually serves the appropriate data.
keyserver: Offering a Thread to serve a key

Now you can call this thread in order to start the server.
One should probably pass arguments to the actual server somehow.
Created a Gtk program which uses the Python threaded server

It seems to work well enough to mix the Gtk mainloop and Python threads.
Keyserver: Moved serve_key to a Thread subclass for use with Gtk mainloop

This allows to run the Keyserver with a Gtk Application, as demoed
with the attached GtkKeyserver program.
Keyserver: Made it use the main thread for initialising the port
Keyserver: serve_key doesn't receive any arguments anymore
Keyserver: Create a Thread when in standalone mode

Now you can run the Keyserver on its own.
Merge branch 'keyserver' into avahi_keyserver
Keyserver: made it Avahi aware, only works partially, though

There is some subtle DBus issue.
GtkKeyserver: Call DBusGMainLoop to make dbus work

I don't really understand why I need to do this and why I cannot do it
in the Avahi class.  Only this way seems to work though.

The error is the following:

python GtkKeyserver.py
/usr/lib/python2.7/dist-packages/gobject/constants.py:24: Warning: g_boxed_type_register_static: assertion 'g_type_from_name (name) == 0' failed
  import gobject._gobject
root (DEBUG): Running main with args: ['GtkKeyserver.py']
root (DEBUG): Starting main
root (DEBUG): toggled button
root (DEBUG): I am being switched on
root (INFO): Serving now
root (DEBUG): About to call <class 'Keyserver.ServeKeyThread'>
root (INFO): Starting thread <ServeKeyThread(Thread-1, initial daemon)>
root (INFO): Trying port 9001
root (INFO): Trying to add Avahi Service
Traceback (most recent call last):
  File "GtkKeyserver.py", line 43, in on_button_toggled
    self.setup_server()
  File "GtkKeyserver.py", line 56, in setup_server
    self.keyserver.start()
  File "/tmp/geysign-branches/Keyserver.py", line 92, in start
    ap.add_service()
  File "/tmp/geysign-branches/AvahiPublish.py", line 46, in add_service
    self.entry_group_state_changed)
  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 544, in connect_to_signal
    dbus_interface, **keywords)
  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 369, in connect_to_signal
    **keywords)
  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 148, in add_signal_receiver
    path, **keywords)
  File "/usr/lib/python2.7/dist-packages/dbus/connection.py", line 400, in add_signal_receiver
    self._require_main_loop()
RuntimeError: To make asynchronous calls, receive signals or export objects, D-Bus connections must be attached to a main loop by passing mainloop=... to the constructor or calling dbus.set_default_main_loop(...)
tmp rename
Merging the rename of the avahi scripts

in preparation for a later merge.
Merge branch 'avahi_keyserver_rename' into avahi_keyserver
Merge branch 'network' into integrate_avahi_keyserver

Conflicts:
	network/AvahiDiscover.py
	network/AvahiPublisher.py
Fixed arguments name for AvahiPublisher
AvahiPublisher: Saved the group in the a field of the class

We never assigned self.group, so it was always None.
Keyserver: Also remove the Avahi Service when shutting down