Test creator doesn't validate or export

[BrechtDeMan]

From other user:

The "Comment Questions" tab seems to be what causes the validate and export options to stop working. As soon as I try to add one, everything seems to freeze.

The "Page Title" and "Comment box test prefix" never show up when I start the survey and the next time I go into the test_create.html the sections are blank, even if I've added something the last time I exported.

On that note, the "Show Fragment Comments" doesn't work with all the types of tests. I actually would have preferred to use a discrete test so that it's not a slider where they can pick between the options but instead, only three choices they have, but the comment boxes don't show up for those or the timeline, which was another style I was thinking of using.

The "Minimum Wait Time" and the "Minimum/Maximum Selected" options for the pre/post test survey questions do not stay. For my survey I wanted a minimum wartime for each question at 2 seconds just to insure they've read and don't accidentally skip to the next question. For my education question, I wanted to be able to allow them to select a maximum of two options (the highest level they've completed, and the level they are in) but it always defaults back to a maximum of one choice.

This particular XML file, and some others, I've noticed it only allows me to validate once. If it was successful, I can export the XML file, and all successive files will export even if there are issues, and I'll get error messages once I 'boot up' the actual test and it won't run.

other students have been getting the issue of a "commentelement" message when they validate denying them from exporting, but are unable to figure out why.

Latest master branch version.

These can probably be split up into separate issues upon verification and if there's no easy catch-all fix.