implement base-wide.html as an extension of base.html

not quite sure why I didn't think of this initially... too much hacking

incorporealcms/templates/base.html

@@ -10,7 +10,7 @@
 <link rel="stylesheet" href="{{ url_for('static', filename=user_style) }}">
 <link rel="icon" href="{% if config.FAVICON %}{{ config.FAVICON }}{% else %}{{ url_for('static', filename='img/favicon.png') }}{% endif %}">
 
-<div class="site-wrap">
+<div {% block site_class %}class="site-wrap"{% endblock %}>
     {% block header %}
     <div class="header">
         <div class="nav">