Add a "Demo Videos" section, refactor links.

Review Request #6955 — Created Feb. 16, 2015 and submitted — Latest diff uploaded

Information

student-sonar
master
946047a...

Reviewers

This adds a new section to the student view to link to all of our sweet demo
videos. As part of this, I've refactored the links structure to reduce
duplication of code.

Checked all the links and saw that things still worked as expected.