Hide the mouse on the presenter window.

src/main.cpp

@@ -71,6 +71,7 @@ int main(int argc, char *argv[]) {
 
   sf::RenderWindow presenter(*screen_mode,
       "Bezos Loves Slides", sf::Style::None, sf::State::Windowed);
+  presenter.setMouseCursorVisible(false);
 
   presenter.setFramerateLimit(FRAME_LIMIT);
   presenter.setVerticalSyncEnabled(VSYNC);