This fixes two minor inconveniences:
- When closing the chat window and re-showing it from the systray icon, the geometry was not properly restored. The window was always shown in the middle of the screen. Now, one gets the window back with it's actual last position and size.
- It is now possible to not only show the window from the systray icon, but also to close it. This is the way other chat programs do it (Kopete back in the day, Konversation, Quassel IRC etc.)
Adds support for xdg_activation_v1 when calling the application from the
system tray by using KStatusNotifier which supports it.
Listens to XDG_ACTIVATION_TOKEN as it's passed when we are started from
dbus.
