First test Table of Contents.
Affix links to sections in the syllabus.
Add some padding so the section headers.

Now they show up under the navbar.
Don't float affix below md.

The ToC looks terrible floating over text.
Fix ToC on non-syllabus pages.

As Syllabus seems to be the only page on which the ToC makes sense,
it should only really get pulled in on the Syllabus page
Merge pull request #174 from decause/feature/table_of_contents

Feature/table of contents