Merge branch 'master' into develop
Fixes the bug that caused the question set input to remain disabled upon restart.
Fixes the failure-to-focus bug on mobile devices.
Improves Quizlet CORS request error checking.
Improves the 'parse url' error message.
Adds some more flashcard options: already filled out Quizlet URLs.
Moves the controls to the top for better mobile usability.
Adds a 'visit' link to make it easier to visit entered in Quizlet.com URLs.
Fixes bug that causes the visit button to link to empty URLs.
Merge branch 'develop'