With this change KWin core no longer depends on the XLib based composite extension. REVIEW: 107685
This possibly fails on some (older?) ati chip/driver combos -> Waiting for bugreports REVIEW: 103246
SVN_SILENT
All the functionality of Overlay Window is moved to its own class OverlayWindow. It is created and owned by class Scene, since almost all function calls are called from this class. REVIEW: 101866
