Improvement: Use anticipate class declaration instead of include header

git-svn-id: svn+ssh://svn.tuxfamily.org/svnroot/qet/qet/trunk@3224 bfdf4180-ca20-0410-9c96-a3a8aa849046

sources/qetgraphicsitem/diagramtextitem.h

@@ -17,8 +17,13 @@
 */
 #ifndef DIAGRAM_TEXT_ITEM_H
 #define DIAGRAM_TEXT_ITEM_H
-#include <QtGui>
-#include "diagram.h"
+
+#include <QGraphicsTextItem>
+
+class Diagram;
+class QDomElement;
+class QDomDocument;
+
 /**
 	This class represents a selectable, movable and editable text field on a
 	diagram.