Make sure styles are not being added twice to questions [HFP-56]

js/questionset.js

@@ -827,6 +827,9 @@ H5P.QuestionSet = function (options, contentId, contentData) {
     for (var i = 0; i < questionInstances.length; i++) {
       var question = questionInstances[i];
 
+      // Make sure styles are not being added twice
+      $('.question-container:eq(' + i + ')', $myDom).attr('class', 'question-container');
+
       question.attach($('.question-container:eq(' + i + ')', $myDom));
 
       // Listen for image resize