Ensure proper use and location of role="banner"

http://blog.paciellogroup.com/2013/02/using-wai-aria-landmarks-2013/#tablex

http://www.w3.org/TR/wai-aria/roles#banner

_includes/nav-main.html

-<div class="navbar navbar-inverse navbar-fixed-top bs-docs-nav">
+<header class="navbar navbar-inverse navbar-fixed-top bs-docs-nav role="banner"">
   <div class="container">
     <button class="navbar-toggle" type="button" data-toggle="collapse" data-target=".bs-navbar-collapse">
       <span class="sr-only">Toggle navigation</span>
@@ -27,4 +27,4 @@
       </ul>
     </nav>
   </div>
-</div>
+</header>

_layouts/default.html

@@ -12,7 +12,7 @@
     {% include nav-main.html %}
 
     <!-- Docs page layout -->
-    <div class="bs-header" id="content" role="banner">
+    <div class="bs-header" id="content">
       <div class="container">
         <h1>{{ page.title }}</h1>
         <p>{{ page.lead }}</p>