Update art template

[amdrwe]

I'd like to use the provided template to create some art for the vsFIGHTER I just got in the mail, but there's a small issue: the two (small, round) buttons on the upper corners near the screws are missing corresponding cutouts in the template. I assume they are a recent addition.

It would also be nice if the readme included some info on what those buttons do (or indeed any of the buttons), but the template is my primary issue right now.