connect toplevel to in-loop screenCount() signal

required because Screens::changed is emitted queued in case of timer shortcut
since a direct signal would cause problems on screen resizes (or rotations,
for that matter) since at that time QDesktopWidget::screenGeometry(int) -xrandr-
is updated, but QDesktopWidget::screen(int)->geometry() (root window) is NOT,
resulting in an invalid value in geometry.cpp/Workspace::desktopResiized(),
thus a "capped" overlay window

However, w/o the count updated we re-encounter what RR 110119 was supposed to fixed
in the first place ...

REVIEW: 110385
BUG: 319848
FIXED-IN: 4.11

toplevel.cpp

@@ -56,6 +56,7 @@ Toplevel::Toplevel()
 {
     connect(this, SIGNAL(damaged(KWin::Toplevel*,QRect)), SIGNAL(needsRepaint()));
     connect(screens(), SIGNAL(changed()), SLOT(checkScreen()));
+    connect(screens(), SIGNAL(countChanged(int,int)), SLOT(checkScreen()));
     setupCheckScreenConnection();
 }