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/scss/views.scss

@@ -57,8 +57,6 @@ All rights reserved.
         position: absolute; bottom: 5em; height: 3.2em; width: 100%;
 
         .login {
-            display: none; // Temporarily disable until there's a feature which needs it
-
             position: absolute; top: 50%; right: 2em;
             @include transform(translateY(-50%));