Enable VSync to prevent screen tearing while scrolling across map

Fixes #2935

client/renderSDL/ScreenHandler.cpp

@@ -275,7 +275,7 @@ void ScreenHandler::initializeWindow()
 	}
 
 	//create first available renderer if preferred not set. Use no flags, so HW accelerated will be preferred but SW renderer also will possible
-	mainRenderer = SDL_CreateRenderer(mainWindow, getPreferredRenderingDriver(), 0);
+	mainRenderer = SDL_CreateRenderer(mainWindow, getPreferredRenderingDriver(), SDL_RENDERER_PRESENTVSYNC);
 
 	if(mainRenderer == nullptr)
 		throw std::runtime_error("Unable to create renderer\n");
@@ -570,4 +570,4 @@ bool ScreenHandler::hasFocus()
 {
 	ui32 flags = SDL_GetWindowFlags(mainWindow);
 	return flags & SDL_WINDOW_INPUT_FOCUS;
-}
+}