preference generation implemented 


git-svn-id: https://gnunet.org/svn/gnunet@32256 140774ce-b5e7-0310-ab8b-a85725594a96
property generation


git-svn-id: https://gnunet.org/svn/gnunet@32257 140774ce-b5e7-0310-ab8b-a85725594a96