CLONE - A history of each wiki page is available

1. Login as student1 and access a wiki activity.
2. Edit the page and add a tag.
3. Add a page comment.
4. Login as student2 and edit the same page.
5. Login as student3 and edit the same page.
6. Check that the history shows a list of page changes together with the user, time and date.
7. Check that the history also shows radio buttons for comparing different versions and links to each version of the page.