window.window should work under JSDom

[kitsonk]

Bug

The window when jsdom is loaded should contain a reference to itself under the window.window property. This is to help ensure that when code tries to grab a reference to the global scope, that it will be able to have a reference to the window without assuming it is actually the global scope.

[kitsonk]

This doesn't appear to be an issue in reality, but added PR #11 to ensure this works as expected.