Changes to incorporate screenlocker into ksmserver.

kscreenlocker is now a static library linked against
libkdeinit4_ksmserver.so. There is still another executable
(kscreenlocker_greet) that is responsible for drawing the QML unlock
screen (the one with the clock). I changed ksmserver to close
screenlocker right before closing the window manager, that is needed to
prevent kwin from becoming a "zoombie". Because of that sometimes you
will still be able to see the home screen right before the computer
finally shuts down.