Adds CompositionTargetEx to avoid rendering without new RenderingTime
Adds Direct3DUserControl as a cusotm SwapChainPanel
Changes SwapChainPanelTarget to get Width and Height from panel. UpdateForSizeChange is called on panel.SizeChanged instead of Window.Current.CoreWindow.SizeChanged.
Removes SizeChanged event listening from Direct3DUserControl, as this is done by SwapChainPanelTarget itself.
Removes dirty init from App.xaml.cs and MainPage.xaml.cs, makes MainPage a normal Page and no more SwapChainPanel