Game Loop Markdown file edits

This pull request includes edits to the Game Loop Markdown file. Most changes were very minor! 

The only item of note was that I changed "shuck their skin off" to "look under the hood" since I usually associate shucking with husks rather than skin. I am not 100% in love with the new metaphor I chose though, so I will not be heartbroken if you reject that change, and I will let you know if I think of something better.