All callback from a widget into a module (e.g. for retrieving the status
or the criticality state) now get a widget passed. This has the purpose
of allowing a module to store state/widget specific data somewhere. This
way, for instance, it is possible to store the interface name as part of
the widget, thus making it possible to show the status of the correct
interface.
* cpu+memory: Open "gnome-system-monitor"
* disk: Open nautilus
* pulseaudio: Mute/unmute, open "pavucontrol" on right-click, raise/lower
volume on mouse wheel up/down
Pass the "output" object to the modules' constructor to allow them to
define their own callbacks.
Any user-provided callbacks take precedence and override those of the
module.
Add a new module "disk" that takes an optional parameter (the path) and
displays free & total disk space, along with the usage percentage.
Also, added Tunnel/VPN support to the themeing of the "net" module.
