Item8402: 

   * new TopicType SeoTopic 
   * added Seo foo to BlogEntries 
   * fixed the way atom feeds are blended in
   * fixed default page cache settings for a blog's webhome
   * allow the comment system to be set per page
   * added microdata where appropriate



git-svn-id: http://svn.foswiki.org/trunk@17048 0b4bb1d4-4e5a-0410-9cc4-b2b747904278