Item12717:

   * declare use of Foswiki::Time 
   * removed code triplication and simplified code
   * fixed inconsistent expansion of variables in html, plain and diff sections



git-svn-id: http://svn.foswiki.org/trunk/MailerContrib@17236 0b4bb1d4-4e5a-0410-9cc4-b2b747904278