Add entry for the libravatar plugin in the Plugin Description table

Readme.rst

@@ -98,6 +98,8 @@ Image Process             Automates the processing of images based on their clas
 
 Interlinks                Lets you add frequently used URLs to your markup using short keywords
 
+Libravatar                Allows inclusion of user profile pictures from libravatar.org
+
 Liquid-style tags         Allows liquid-style tags to be inserted into markdown within Pelican documents
 
 Multi parts posts         Allows you to write multi-part posts