Add additional roles and move "main" roles into the proper places (hopefully)

Author: Lou Huang

_layouts/customize.html

@@ -12,7 +12,7 @@
     {% include nav-main.html %}
 
     <!-- Docs page layout -->
-    <div class="bs-header" id="content" role="main">
+    <div class="bs-header" id="content" role="banner">
       <div class="container">
         <h1>{{ page.title }}</h1>
         <p>{{ page.lead }}</p>
@@ -23,7 +23,7 @@ <h1>{{ page.title }}</h1>
     <!-- Callout for the old docs link -->
     {% include old-bs-docs.html %}
 
-    <div class="bs-customize-placeholder">
+    <div class="bs-customize-placeholder" role="main">
       <div class="container bs-docs-container">
         <p class="lead">Until RC2, the Bootstrap 3 customizer will be disabled. In the mean time, snag the <a href="{{ site.repo }}/releases">compiled CSS and JavaScript</a>. Hang tight!</p>
       </div>

_layouts/default.html

@@ -12,7 +12,7 @@
     {% include nav-main.html %}
 
     <!-- Docs page layout -->
-    <div class="bs-header" id="content" role="main">
+    <div class="bs-header" id="content" role="banner">
       <div class="container">
         <h1>{{ page.title }}</h1>
         <p>{{ page.lead }}</p>
@@ -26,7 +26,7 @@ <h1>{{ page.title }}</h1>
     <div class="container bs-docs-container">
       <div class="row">
         <div class="col-lg-3">
-          <div class="bs-sidebar">
+          <div class="bs-sidebar" role="complementary">
             <ul class="nav bs-sidenav">
               {% if page.slug == "getting-started" %}
                 {% include nav-getting-started.html %}
@@ -42,7 +42,7 @@ <h1>{{ page.title }}</h1>
             </ul>
           </div>
         </div>
-        <div class="col-lg-9">
+        <div class="col-lg-9" role="main">
           {{ content }}
         </div>
       </div>
@@ -51,7 +51,7 @@ <h1>{{ page.title }}</h1>
 
     <!-- Footer
     ================================================== -->
-    <footer class="bs-footer">
+    <footer class="bs-footer" role="contentinfo">
       {% include social-buttons.html %}
 
       <p>Designed and built with all the love in the world by <a href="http://twitter.com/mdo" target="_blank">@mdo</a> and <a href="http://twitter.com/fat" target="_blank">@fat</a>.</p>

_layouts/home.html

@@ -17,7 +17,7 @@
     <!-- Callout for the old docs link -->
     {% include old-bs-docs.html %}
 
-    <div class="container" id="content" role="main">
+    <div class="container" role="contentinfo">
       {% include social-buttons.html %}
 
       <ul class="bs-masthead-links">

index.html

@@ -4,7 +4,7 @@
 base_url: "./"
 ---
 
-<div class="bs-masthead" id="content">
+<div class="bs-masthead" id="content" role="main">
   <div class="container">
     <h1>Bootstrap 3</h1>
     <p class="lead">Sleek, intuitive, and powerful mobile-first front-end framework for faster and easier web development.</p>