Convert site to a single JavaScript archive

* Convert build to use a single JavaScript file on the site (instead
  of downloading each library separately). This also means that all
  global variables (e.g., `$` for JQuery, `_` for Underscore.js) can
  be removed.
* Remove unused scripts and/or move them to a more appropriate repo
* Update the `deploy` script to work with CircleCI's automation
* Update markdown display code to allow images to be located with the
  markdown data files instead of the pre-rendered index pages

src/coffee/controllers/item_page_controller.coffee

@@ -15,6 +15,7 @@ ItemSlug                  = require '../models/item_slug'
 MarkdownSectionController = require './markdown_section_controller'
 PageController            = require './page_controller'
 VideoController           = require './video_controller'
+_                         = require 'underscore'
 {Duration}                = require '../constants'
 {Event}                   = require '../constants'
 {Text}                    = require '../constants'
@@ -88,6 +89,8 @@ module.exports = class ItemPageController extends PageController
             @imageLoader.load display.iconUrl, @$titleImage
             @$name.html display.itemName
 
+            @_descriptionController.imageBase = Url.itemImageDir display
+
             if @model.item.officialUrl?
                 @$officialPageLink.attr 'href', @model.item.officialUrl
                 @show @$officialPageLink