[NUI] Support Layout for Multi-Window

[NUI] Support Layout for Multi-Window

Previously, Layouts in the default Window were supported.

Now, Layouts in all Windows are supported.

To enable Multi-Window, Window.IsSupportedMultiWindow() should be true
and the following code should not be executed.

Information.TryGetValue("http://tizen.org/feature/opengles.surfaceless_context", out isSupported);