Fix version display in the HTML title (#249)

Forgot to remove the tags when including the version number in the HTML
title. Use the `striptags` filter to fix this in the base template.

doc/_templates/layout.html

@@ -21,6 +21,6 @@
     {% if title == '' or title == 'Home' %}
         <title>{{ docstitle|striptags|e }}</title>
     {% else %}
-        <title>{{ title|striptags|e }}{{ titlesuffix }}</title>
+        <title>{{ title|striptags|e }} | {{ docstitle|striptags|e }}</title>
     {% endif %}
 {% endblock %}