Added favicon in opds feed

Merge remote-tracking branch 'favicon/master'

cps/templates/feed.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <feed xmlns="http://www.w3.org/2005/Atom" xmlns:dc="http://purl.org/dc/terms/" xmlns:dcterms="http://purl.org/dc/terms/">
+  <icon>{{ url_for('static', filename='favicon.ico') }}</icon>
   <id>urn:uuid:2853dacf-ed79-42f5-8e8a-a7bb3d1ae6a2</id>
   <updated>{{ current_time }}</updated>
   <link rel="self"

cps/templates/index.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <feed xmlns="http://www.w3.org/2005/Atom">
+  <icon>{{ url_for('static', filename='favicon.ico') }}</icon>
   <id>urn:uuid:2853dacf-ed79-42f5-8e8a-a7bb3d1ae6a2</id>
   <updated>{{ current_time }}</updated>
   <link rel="self" href="{{url_for('opds.feed_index')}}" type="application/atom+xml;profile=opds-catalog;kind=navigation"/>