Make it possible to have implementations in different toolkits.

Also, make it possible to share the headers.

OGWindow.h

@@ -1,22 +0,0 @@
-#import "OGWidget.h"
-
-@class OGWindow;
-
-@protocol OGWindowDelegate <OFObject>
-@optional
-- (BOOL)windowWillClose: (OGWindow*)window;
-@end
-
-@interface OGWindow: OGWidget
-{
-	id <OGWindowDelegate> delegate;
-}
-
-@property (assign) id <OGWindowDelegate> delegate;
-@property (copy) OFString *title;
-@property (assign) of_point_t position;
-@property (assign) of_dimension_t dimension;
-
-+ window;
-- (void)addChild: (OGWidget*)widget;
-@end