README.md: added link to the revision control material.
Version-control.ppt: one or two changes.
Version-control.ppt: changed some of the content a little and I added some content.
Version-control.ppt: added conent - downloading the student material.
Merge branch 'students' of https://github.com/mikej888/2013-12-03-edinburgh into students
Merge pull request #3 from marioa/students

Students