removing imageButton and menuButton stuff. obsolete.

widget/public/MANIFEST

@@ -38,11 +38,8 @@ nsILookAndFeel.h
 nsWidgetSupport.h
 nsIMenu.h
 nsIMenuBar.h
-nsIMenuButton.h
 nsIMenuItem.h
 nsIPopUpMenu.h
-nsIImageButton.h
-nsIImageButtonListener.h
 nsIContentConnector.h
 nsIKeyBindMgr.h
 nsStringUtil.h