Adds some more flashcard options: already filled out Quizlet URLs.
Adds the preloaded quizlet URL feature as well as some default options.
Moves the controls to the top for better mobile usability.
Merges control bar change from develop.
Adds a 'visit' link to make it easier to visit entered in Quizlet.com URLs.
Merge branch 'develop' into gh-pages

Conflicts:
	js/game_manager.js
Adds more Google Analytics events.