It didn't feel right to have a "DHCPClient" in a "Servers" directory.
Rename this to Services to better reflect the type of programs we'll
be putting in there.
When clicking the window icon, we now pop up the window menu at the
bottom left of the icon, no matter where you clicked it.
Right-clicking the title bar still pops up at the event position.
This patch adds a specialized window type for notifications. They now
have a title bar on the right-hand side, with a close button.
This removes the need for the "Done" button in notifications, giving us
a bit more horizontal space overall.
Design based on a mock-up from @xTibor :^)
