Implement QCocoaWindow::setWindowState.

Implement QCocoaWindow::setWindowState.

Add window state change notification logic. Send
and expose event in addition to window state change
on window restore since the QWidget logic expects
this.

Modify QCocoaWindow::setVisible to sync up window
state that may have been set on the hidden window.

Refactor NSWindow event observing to use one observer
function for all notifications.

Add window state testing to tests/manual/windowflags
Add delay after showFullScreen in tst_qstatusbar to
wait for the Lion fullscreen transition.

Change-Id: I57c523cedd0644d4181b40d72046fad4fdb09a9c
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>