move gihelper to own class from namespace

This action will allow to store data in the helper class. Also
notification for high memory usage has been changed from 90 to 80.

sources/awesomewidgets/graphicalitem.h

@@ -23,6 +23,7 @@
 #include "abstractextitem.h"
 
 
+class GraphicalItemHelper;
 class QGraphicsScene;
 class QGraphicsView;
 
@@ -97,6 +98,7 @@ private slots:
     void changeValue(const int state);
 
 private:
+    GraphicalItemHelper *m_helper = nullptr;
     QGraphicsScene *m_scene = nullptr;
     QGraphicsView *m_view = nullptr;
     Ui::GraphicalItem *ui;