private SlideshowDriver(SlideshowModel model, ISlideshowViewer viewer, IPlatformService platformService)
		{
			PlatformService = platformService;
			Model = model;
			Viewer = viewer;
			State = DriverState.Created;
		}
		static public SlideshowDriver Create(SlideshowModel model, ISlideshowViewer viewer, IPlatformService platformService)
		{
			var driver = new SlideshowDriver(model, viewer, platformService);
			driver.BeginEnumerate();
			return driver;
		}
		static public SlideshowDriver Create(string filename, ISlideshowViewer viewer, IPlatformService platformService)
		{
			return Create(SlideshowModel.ParseFile(filename), viewer, platformService);
		}