Added editing star rating graphically

Added ability to reload database connection (refresh problem)
Bugfix display hot books (no hot books, hot books are deleted books, no longer result in error 500)

cps/templates/feed.xml

@@ -35,6 +35,7 @@
     <uri>https://github.com/janeczku/calibre-web</uri>
   </author>
 
+  {% if entries[0] %}
   {% for entry in entries %}
   <entry>
     <title>{{entry.title}}</title>
@@ -60,6 +61,7 @@
     {% endfor %}
   </entry>
   {% endfor %}
+  {% endif %}
   {% for entry in listelements %}
   <entry>
     <title>{{entry.name}}</title>