Strip tags from title in simple index. Fixes #612

This fix was applied previously to the relevant places in both the
"simple" and "notmyidea" themes, but the simple theme's index.html file
was apparently neglected.

pelican/themes/simple/templates/index.html

@@ -1,14 +1,14 @@
 {% extends "base.html" %}
-{% block content %}        
+{% block content %}
 <section id="content">
 {% block content_title %}
 <h2>All articles</h2>
 {% endblock %}
 
 <ol id="post-list">
-{% for article in articles_page.object_list %}        
-        <li><article class="hentry">    
-                <header> <h2 class="entry-title"><a href="{{ SITEURL }}/{{ article.url }}" rel="bookmark" title="Permalink to {{ article.title}}">{{ article.title }}</a></h2> </header>
+{% for article in articles_page.object_list %}
+        <li><article class="hentry">
+                <header> <h2 class="entry-title"><a href="{{ SITEURL }}/{{ article.url }}" rel="bookmark" title="Permalink to {{ article.title|striptags }}">{{ article.title }}</a></h2> </header>
                 <footer class="post-info">
                     <abbr class="published" title="{{ article.date.isoformat() }}"> {{ article.locale_date }} </abbr>
                     {% if article.author %}<address class="vcard author">By <a class="url fn" href="{{ SITEURL }}/{{ article.author.url }}">{{ article.author }}</a></address>{% endif %}