Add the beginnings of charts

This commit adds a lot of files, but most of them have no impact on any
other code. The thrust here is to start creating chart pages showing
which tracks and artists were most played for various time periods. Lots
still not working, but we're getting there.

vrobbler/templates/music/track_detail.html

@@ -0,0 +1,13 @@
+{% extends "base_detail.html" %}
+
+{% block title %}{{object.title}}{% endblock %}
+
+{% block details %}
+<h2>Last scrobbles</h2>
+{% for scrobble in object.scrobble_set.all  %}
+<ul>
+    <li>{{scrobble.timestamp|date:"d M Y h:m"}} - <img src="{{object.album.cover_image.url}}" width=25 height=25 /> - {{object}}</li>
+</ul>
+{% endfor %}
+
+{% endblock %}