[NFS] Combine borderless windowed modes. Also, add alt+enter key combo

[xan1242]

The stretch mode and scale modes should be combined together.

One way would be to add black bars to the sides of the borderless window.

Another way would be to actually stretch the image but still apply aspect ratio scaling. This would have a very similar result to what Unity games do, for example.

So, it would combine the two modes and add one more option to control how it behaves.

And lastly, an alt+enter would be a nice to have. I don't think this would be too difficult to implement. Just needs a d3d device reset and that's it.