Tomeu

* Remove volume.py from the model and use instead gio

* Remove volume.py from the model and use instead gio

* Substitute gnomevfs with gio

* Substitute gnomevfs with gio http://dev.sugarlabs.org/ticket/28

* Monitor changes in the removable device filesystem and update the view accordingly

* Monitor changes in the removable device filesystem and update the view accordingly

* Add signature annotations for dbus methods in the view source stuff.

* Add signature annotations for dbus methods in the view source stuff.