Sample glTF files fail to load in Microsoft's own software

[Leadwerks]

The files "glTF-Toolkit/glTF-Toolkit.Test/Resources/gltf/CubeAsset3D.gltf" and "glTF-Toolkit/glTF-Toolkit.Test/Resources/gltf/CubeWithLOD.gltf" fail to load in both Windows explorer preview pane and the Windows 10 3D Viewer program by Microsoft.

[bghgary]

I'm not sure I would call these assets sample glTF files as they are test files, but they don't load because the glTF files don't have a URI in the buffer object. They don't load in any software that I tried.