Improved context sensitive help

- create utilty function CGuiApplication::triggerShowHelp
- this function also uses "QWhatsThis::leaveWhatsThisMode" which solves the problem that the help was not properly called a 2nd time
- adjusted using classes

src/blackgui/components/interpolationlogdisplaydialog.h

@@ -48,6 +48,10 @@ namespace BlackGui
             //! Set airspace monitor
             void setAirspaceMonitor(BlackCore::CAirspaceMonitor *airspaceMonitor);
 
+        protected:
+            //! \copydoc QObject::event
+            virtual bool event(QEvent *event) override;
+
         private:
             QScopedPointer<Ui::CInterpolationLogDisplayDialog> ui;
         };