This commit fixes the issues with updates being reported after having
already installed them.
Moreover, to improve the communication to user, a new signal "updating_signal"
is spawned before the repositories sync.
With this commit the work on the client (system) updates daemon is
complete. The *thing* works over dbus, exporting a bunch of methods
and sending signals whenever new updates are downloaded.
For more information look at the file itself, for now.
When the daemon is loaded, it should not take over the pid file.
Also, before trying to update the repositories, it should check
if the same resources are locked by something else.
