Docs: Refactor to use .less file instead, importing Bootstrap vars and mixins, and cleaning all the things up

docs/_includes/header.html

@@ -29,12 +29,7 @@
 {% endif %}
 
 <!-- Documentation extras -->
-{% if site.github %}
 <link href="../assets/css/docs.min.css" rel="stylesheet">
-{% else %}
-<link href="../assets/css/src/docs.css" rel="stylesheet">
-<link href="../assets/css/src/pygments-manni.css" rel="stylesheet">
-{% endif %}
 <!--[if lt IE 9]><script src="../assets/js/ie8-responsive-file-warning.js"></script><![endif]-->
 <!-- IE10 viewport hack for Surface/desktop Windows 8 bug -->
 <script src="../assets/js/ie10-viewport-bug-workaround.js"></script>

docs/_includes/nav/docs.html

@@ -8,8 +8,7 @@
         <span class="icon-bar"></span>
       </button>
       <a href="../" class="navbar-brand">
-        <span class="visible-xs">Bootstrap</span>
-        <span class="bs-docs-booticon bs-docs-booticon-md hidden-xs">B</span>
+        Bootstrap
       </a>
     </div>
     <nav class="collapse navbar-collapse bs-sidenav-collapse" role="navigation">