[GitHub] Warn users if they have inadequate computer specs [xsera/xsera GH-3]

[GitHub]

If a computer is unable to use certain graphics options or cannot display Xsera at a rate greater than 30 FPS, warn them on startup that their gameplay experience might not be as good as on a faster computer.

View this Issue online: http://github.com/xsera/xsera/issues#issue/3