gdkwindow-quartz: Support native fullscreen mode

This implements native fullscreen mode on OS X >= 10.7. This patch
adds tracking of the fullscreen mode if externally modified, as well
as toggling the native fullscreen mode of the window as needed.

gdk/quartz/GdkQuartzNSWindow.h

@@ -42,6 +42,7 @@
 -(BOOL)trackManualResize;
 -(void)showAndMakeKey:(BOOL)makeKey;
 -(void)hide;
+-(void)setStyleMask:(NSUInteger)styleMask;
 
 @end