Merge pull request #14 from janmeier/master

Fix issues 441, 442 and 443. Also added a bit more logging to enrolments
Changed the wording in the waiting list conf. email
Slight performance improvements on the view datecourse page
Prevent the user from saving a metacourse with no dates
Only allow coordinators to enrol others
Add a dedicated table to store meta course views. Improves performance when counting the number of views
Move the process of upgrading old log entries for meta course views into a separate script
Changed how the participant report is generated