Clean headers in Designer.

Ran script to remove inludes on a trial-and-error basis and
manually corrected it.

Change-Id: Ia97b5bd9e4496cd824f35c5fda8ccf0db9af471c
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

src/plugins/designer/settingspage.cpp

@@ -28,10 +28,8 @@
 ****************************************************************************/
 
 #include "settingspage.h"
-#include "designerconstants.h"
 #include "formeditorw.h"
 
-#include <extensionsystem/pluginmanager.h>
 #if QT_VERSION >= 0x050000
 #    include <QDesignerOptionsPageInterface>
 #else
@@ -39,7 +37,6 @@
 #endif
 
 #include <QCoreApplication>
-#include <QIcon>
 
 using namespace Designer::Internal;