Add Code Formatting Article

IMO a _very_ important article to have to point people to that don't understand how to format code in the forums. Definitely something that I think @fanaugen, @sharocko, and @gracenut in particular should have input in so that it is a good place to point people when editing posts for code formatting (the previous place we did this was a [JSBin project](http://jsbin.com/akewog/1) that @fanaugen made... But something hosted on codecademy.com would be much better ;)

Also, I think that this should eventually go in `./published/Q&A\ Forums/` because of its applicability with the Q&A Forums Codecademy product - but it could also debatably go in a Groups section... Thoughts?