Item12489:Item12442:

  * cleaning up old thumbnails when attachments are moved or renamed
  * fixing optional depencency on XSendFileContrib
  * fixed some more svg support
  * removed stale code to base64 encode thumnail urls



git-svn-id: http://svn.foswiki.org/trunk/ImagePlugin@16703 0b4bb1d4-4e5a-0410-9cc4-b2b747904278