SFML: disable vsync for now

platform/sfml/Graphics.cpp

@@ -12,7 +12,6 @@ sf::RenderTexture buffer;
 void GRAPHICS::init()
 {
     window.create(sf::VideoMode::getDesktopMode(), "WalrusRPG", sf::Style::Fullscreen);
-    window.setVerticalSyncEnabled(true);
     window.setFramerateLimit(60);
     view = sf::View(window.getDefaultView());
     buffer.create(320, 240);