Update opds feed with letters for all titles, authors, categories and series

cps/templates/feed.xml

@@ -84,4 +84,11 @@
     <link rel="subsection" type="application/atom+xml;profile=opds-catalog" href="{{url_for(folder, book_id=entry.id)}}"/>
   </entry>
   {% endfor %}
+  {% for entry in letterelements %}
+  <entry>
+    <title>{{entry['name']}}</title>
+    <id>{{ url_for(folder, book_id=entry['id']) }}</id>
+    <link rel="subsection" type="application/atom+xml;profile=opds-catalog" href="{{url_for(folder, book_id=entry['id'])}}"/>
+  </entry>
+  {% endfor %}
 </feed>

cps/templates/index.xml

@@ -16,8 +16,8 @@
   </author>
   <entry>
     <title>{{_('Alphabetical Books')}}</title>
-    <link href="{{url_for('opds.feed_books')}}" type="application/atom+xml;profile=opds-catalog"/>
-    <id>{{url_for('opds.feed_books')}}</id>
+    <link href="{{url_for('opds.feed_booksindex')}}" type="application/atom+xml;profile=opds-catalog"/>
+    <id>{{url_for('opds.feed_booksindex')}}</id>
     <updated>{{ current_time }}</updated>
     <content type="text">{{_('Books sorted alphabetically')}}</content>
   </entry>