Garrett branch

Things done:
Overflow is scrollable
Button, font style is correct

Comments:
The navigation panel is now independent of the slides (base template: 'table_of_contents_base.html'). The transitions still momentarily overlap while transitioning, however. 

Stile to do:
Create 'add files' alternative panel, triggered by 'Add +' button (and the corresponding code behind it
Front page search styling
Minor styling (Add + button is still slightly off, etc.)