Exposes the extended window style on Window objects (PR #9136)
For application Windows, the window style can be fetched to find out whether the window has a title bar, is visible or unavailable. The extended window style wasn't yet available on Window objects. The "extended window style" (see msdn) provides information like:
* Whether the window supports dragging and dropping of files
* Whether the window is a window within an MDI interface
* Whether the window text is displayed using right-to-left reading-order properties
* Whether the window is a floating toolbar
* Whether the window is transparent
* The window is always on top
