Refactored inclusion of disqus script

- Added ARIA setting `aria-live="polite"` to comment output
- Removed duplicate <div id="disqus_thread"> from page/post templates
- Moved blocking JavaScript loading to the end of the document body.
- Merged JavaScript code for index and pages/posts using conditionals
- Moved global JavaScript disqus variables into the anonymous function to stop pollution of global namespace

.themes/classic/source/_includes/disqus.html

@@ -0,0 +1,22 @@
+{% comment %} Load script if disquss comments are enabled and `page.comments` is either empty (index) or set to true {% endcomment %}
+{% if site.disqus_short_name and page.comments != false %}
+<script type="text/javascript">
+    (function () {
+      var disqus_shortname = '{{ site.disqus_short_name }}';
+      {% if page.comments == true %}
+        {% comment %} `page.comments` can be only be set to true on pages/posts, so we embed the comments here. {% endcomment %}
+        // var disqus_developer = 1;
+        var disqus_identifier = '{{ site.url }}{{ page.url }}';
+        var disqus_url = '{{ site.url }}{{ page.url }}';
+        var disqus_script = 'embed.js'
+      {% else %}
+        {% comment %} As `page.comments` is empty, we must be on the index page. {% endcomment %}
+        var disqus_script = 'count.js'
+      {% endif %}
+
+      var dsq = document.createElement('script'); dsq.type = 'text/javascript'; dsq.async = true;
+      dsq.src = 'http://' + disqus_shortname + '.disqus.com/' + disqus_script;
+      (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(dsq);
+    }());
+</script>
+{% endif %}

.themes/classic/source/_includes/post/disqus_thread.html

@@ -1,13 +1 @@
-<div id="disqus_thread"></div>
-<script type="text/javascript">
-  var disqus_shortname = '{{ site.disqus_short_name }}';
-  var disqus_identifier = '{{ site.url }}{{ page.url }}';
-  var disqus_url = '{{ site.url }}{{ page.url }}';
-  //var disqus_developer = 1;
-  (function() {
-    var dsq = document.createElement('script'); dsq.type = 'text/javascript'; dsq.async = true;
-    dsq.src = 'http://' + disqus_shortname + '.disqus.com/embed.js';
-    (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(dsq);
-  })();
-</script>
 <noscript>Please enable JavaScript to view the <a href="http://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript>

.themes/classic/source/_layouts/default.html

@@ -9,6 +9,7 @@
     </div>
   </div>
   <footer>{% include footer.html %}</footer>
+  {% include disqus.html %}
   {% include google_analytics.html %}
   {% include google_plus_one.html %}
   {% include twitter_sharing.html %}

.themes/classic/source/_layouts/page.html

@@ -27,7 +27,7 @@ layout: default
 {% if site.disqus_short_name and page.comments == true %}
   <section>
     <h1>Comments</h1>
-    <div id="disqus_thread">{% include post/disqus_thread.html %}</div>
+    <div id="disqus_thread" aria-live="polite">{% include post/disqus_thread.html %}</div>
   </section>
 {% endif %}
 </div>

.themes/classic/source/_layouts/post.html

@@ -17,10 +17,10 @@ single: true
     {% endunless %}
   </footer>
 </article>
-{% if site.disqus_short_name and page.comments != false %}
+{% if site.disqus_short_name and page.comments == true %}
   <section>
     <h1>Comments</h1>
-    <div id="disqus_thread">{% include post/disqus_thread.html %}</div>
+    <div id="disqus_thread" aria-live="polite">{% include post/disqus_thread.html %}</div>
   </section>
 {% endif %}
 </div>

.themes/classic/source/index.html

@@ -21,17 +21,6 @@ layout: default
       {% endif %}
     </div>
   </nav>
-{% if site.disqus_short_name %}
-<script type="text/javascript">
-    var disqus_shortname = '{{ site.disqus_short_name }}';
-    (function () {
-      var s = document.createElement('script'); s.async = true;
-      s.type = 'text/javascript';
-      s.src = 'http://' + disqus_shortname + '.disqus.com/count.js';
-      (document.getElementsByTagName('HEAD')[0] || document.getElementsByTagName('BODY')[0]).appendChild(s);
-    }());
-</script>
-{% endif %}
 </div>
 <aside role=sidebar>
   {% if site.blog_index_asides.size %}