Merge pull request #20 from pocket-gophers-2014/styling

Styling
Added viewHelper for prettify code that creates handlebars safe string with pre tags and then runs prettify with aftermodel callback as before
  TODO: make spacing nicer on linums so it doesn't push code over
  TODO: change font color of loading message
Fixed bug in HTML rendering in the prettify ember helper method. Moved content injection to afterModel callback that executes App.PrettifyView.refresh().