Set up server-side router

[AndrewMagliozzi]

Serve routes for the index page, each text, and annotations. These will constitute three separate backbone applications. This will scale well when we add separate applications for Groups and Folders.

• Change template in WorkNavView
• Implement routes on the backend
• Restructure Backbone app as separate apps
• Add comments here about methodology for server logic (header, footer, site, etc.)
• Set up sessions in Express for breadcrumbing