We currently use icon paths for this because I didn't want to deal with
implementing icon bitmap sharing right now. In the future it would be
better to post a bitmap somehow instead of a path.
Since the returned object is now owned by the callee object, we can
simply vend a ChildType&. This allows us to use "." instead of "->"
at the call site, which is quite nice. :^)
Don't stack notifications on top of each other, instead put them below
one another on the y axis.
This will obviously break if the screen fills with notifications, but
that's a FIXME for now. :^)
This patch adds NotificationServer, which runs as the "notify" user
and provides an IPC API for desktop notifications.
LibGUI gains the GUI::Notification class for showing notifications.
NotificationServer is spawned on demand and will unspawn after
dimissing all visible notifications. :^)
Finally, this also comes with a small /bin/notify utility.
