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/models/crafting_plan.coffee

@@ -9,6 +9,7 @@ BaseModel = require './base_model'
 Inventory = require './inventory'
 ItemSlug  = require './item_slug'
 Step      = require './step'
+_         = require 'underscore'
 {Event}   = require '../constants'
 
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