Unregister raw input device when DDIO shuts down

[InsanityBringer]

This is to avoid problems with the mouse still being captured on an alt-tab.

One thing that I think should be resolved before any release is how mouse capturing will work. In windowed mode, the mouse cursor is shown, but it is still captured and exclusive to the window. Ideally, in windowed mode, the mouse should be visible and not captured when the game is in a UI. During this state, I think I can sync the software cursor with the actual hardware one, since legacy mouse events would be available. When you're actually playing the game, however, the cursor should be invisible and captured to prevent it leaving.