[Gui] So headers: remove some unused includes

- also sort out some headers for precompiled headers

src/Gui/SoFCColorBar.cpp

@@ -20,13 +20,13 @@
  *                                                                         *
  ***************************************************************************/
 
-
 #include "PreCompiled.h"
+
 #ifndef _PreComp_
-# include <Inventor/nodes/SoEventCallback.h>
 # include <Inventor/actions/SoGLRenderAction.h>
-# include <Inventor/nodes/SoSwitch.h>
 # include <Inventor/events/SoMouseButtonEvent.h>
+# include <Inventor/nodes/SoEventCallback.h>
+# include <Inventor/nodes/SoSwitch.h>
 # include <QApplication>
 # include <QMenu>
 #endif
@@ -35,6 +35,7 @@
 #include "SoFCColorGradient.h"
 #include "SoFCColorLegend.h"
 
+
 using namespace Gui;
 
 SO_NODE_ABSTRACT_SOURCE(SoFCColorBarBase)