CtrlLib, Doc: Removed virtual keyword from tutorials in favor of override.

tutorial/Gui04/main.cpp

@@ -3,7 +3,7 @@
 using namespace Upp;
 
 struct MyAppWindow : TopWindow {
-	virtual void Paint(Draw& w) override {
+	void Paint(Draw& w) override {
 		w.DrawRect(GetSize(), SWhite());
 		w.DrawText(20, 20, "Hello world!", Arial(30), Magenta);
 	}

tutorial/Gui05/main.cpp

@@ -6,17 +6,17 @@ struct MyAppWindow : TopWindow {
 	Point  p;
 	String text;
 
-	virtual void LeftDown(Point pos, dword flags) override {
+	void LeftDown(Point pos, dword flags) override {
 		p = pos;
 		Refresh();
 	}
 
-	virtual void MouseMove(Point pos, dword flags) override {
+	void MouseMove(Point pos, dword flags) override {
 		text = Format("[%d:%d]", pos.x, pos.y);
 		Refresh();
 	}
 
-	virtual void Paint(Draw& w) override {
+	void Paint(Draw& w) override {
 		w.DrawRect(GetSize(), SWhite);
 		w.DrawText(p.x, p.y, text, Arial(20), Magenta);
 	}

tutorial/Gui08/main.cpp

@@ -8,7 +8,7 @@ struct MyAppWindow : TopWindow {
 			Break();
 	}
 
-	virtual void RightDown(Point, dword) override {
+	void RightDown(Point, dword) override {
 		MenuBar::Execute(
 			[=](Bar& bar) {
 				bar.Add("Exit", [=] { Exit(); });

tutorial/Gui09/main.cpp

@@ -8,7 +8,7 @@ struct MyAppWindow : TopWindow {
 			Break();
 	}
 
-	virtual void RightDown(Point, dword) override {
+	void RightDown(Point, dword) override {
 		int result = Null;
 		MenuBar menu;
 		for(int i = 0; i < 10; i++)

tutorial/Gui21/main.cpp

@@ -5,12 +5,12 @@ using namespace Upp;
 struct MyCtrl : public Ctrl {
 	int count = 0;
 
-	virtual void Paint(Draw& w) override {
+	void Paint(Draw& w) override {
 		w.DrawRect(GetSize(), White());
 		w.DrawText(2, 2, AsString(count));
 	}
 
-	virtual void LeftDown(Point, dword) override {
+	void LeftDown(Point, dword) override {
 		count++;
 		Refresh();
 	}

tutorial/Gui23/main.cpp

@@ -11,7 +11,7 @@ struct MyAppWindow : TopWindow {
         Zoomable().Sizeable().SetRect(0, 0, 550, 100);
     }
     
-    virtual void Paint(Draw& w) override {
+    void Paint(Draw& w) override {
         w.DrawRect(GetSize(), SLtYellow);
         w.DrawText(20, 20, t_("Hello translation engine!"), Arial(30), Blue);
     }