Changes notifications like:
XChat: Private message from: danw (GimpNet) blah...
to
danw: blah blah blah blah
(the "XChat" being unnecessary since there's already an xchat icon
there anyway.)
https://bugzilla.gnome.org/show_bug.cgi?id=608915
This adds some meaningful functionality to the notification icons in the tray
and in the notification pop-up and allows to switch to the application that
sent the notification.
We get the application from the notification context and set it on the source
for the notification.
