Screenshot in README is broken

[RossComputerGuy]

Can we please have the screenshot that's supposed to show in the README be changed? The current screenshot returns a 404 error code.

[rreusser]

I don't have the time to publish to npm right now, but I've updated the URL directly to http://stackgl.github.io/gl-vao/screenshot.png

No strong feelings (feel free to close, anyone?), but leaving it open since there's still some unhandled domain migration cleanup that this doesn't permanently solve.

[rreusser]

Maybe should fix the CNAME and revert this. See: stackgl/stackgl.github.io#14