proposal: intensive usage of libunique

[Deubeuliou]

libunique makes it possible to create singleton application and thus.
This could be useful to keep highly-used applications running and only hide them:
For instance, the keyboard is launched and killed by neod. It could be called with a "--show" or a "--hide" option and libunique will see that an instance of h1xkbd is already running and send a message to it.

This behaviour could be applied to many other applications (h1settings, wifig, ...).

At last, but not least:
"As of GNOME 2.26, Unique is a GNOME blessed external dependency. "
It also provides a DBus backend.

 http://live.gnome.org/LibUnique

What do you think of it ? Jérôme pointed me to it and IMHO, we should make intensive use of it for the rev6