ZP-475 #comment set the organizer of meeting request responses to the "to" address (user receiving updates is the organizer). In all other cases the "from" is continued to set (as before)

git-svn-id: https://z-push.org/svn/z-push/trunk@1778 b7dd7b3b-3a3c-0410-9da9-bee62a6cc5b5