message: Proper cleanup
diff: @@ -122,6 +122,8 @@ viewer_sdl2::viewer_sdl2(int width, int height, char const* window_title)
  viewer_sdl2::~viewer_sdl2()
  {
  + SDL_GL_DeleteContext(impl_->context);
  + SDL_DestroyWindow(impl_->window);
  }
  void viewer_sdl2::init(int argc, char** argv)
  