cosmetic to MainWindow,

drop does not work for widget,
fixed offset problem,
add esc key

QtMeshViewer/Header/MainWindow.h

@@ -13,4 +13,10 @@ public:
 
 private:
 	Ui::MainWindowClass* ui;
+
+private slots:
+	void openFile();
+	void aboutFile();
+	void aboutTool();
+
 };