Add initial site config, content and copy of "simple" theme.

themes/next.copyleft.org/templates/categories.html

@@ -0,0 +1,12 @@
+{% extends "base.html" %}
+
+{% block title %}{{ SITENAME }} - Categories{% endblock %}
+
+{% block content %}
+    <h1>Categories on {{ SITENAME }}</h1>
+    <ul>
+    {% for category, articles in categories|sort %}
+        <li><a href="{{ SITEURL }}/{{ category.url }}">{{ category }}</a> ({{ articles|count }})</li>
+    {% endfor %}
+    </ul>
+{% endblock %}