Merge pull request #1 from janmeier/master

Fix images in course descriptions and rewriting to / from pluginfile
Set a lot of fields to required.
Merge branch 'master' of https://github.com/henrikthorn/novozymes
Bugfixes
Fixed metacourse name update resulting in creation of new datecourses.,
Fix for deleting courses.
Fixed timestamp transfers and custom e-mails.
Fixed javascript.
Fixed JS and corrected duration that only showed seconds.
Fixed waiting list issues.
Add a few comments, remove any waitlist entries when removing enrollment, and change the logic for checking if a user is already enrolled in a course.