Added header partial

- Replaced old header
- Menu icon needs to be bought / attributed
Differentiate headers between author and expert view
Moved left sidebar into a partial
Added left-sidebar.js

Adds interactivity with the left-sidebar. Will eventually merge into
sidebar.js
Added CSS rules for updating to mock

- Keeping these separate for now
Moved description modal to sidebar, added locals
Merge pull request #37 from ofagbemi/jf-updateHeader

Update header