PSYC: message types, documentation

git-svn-id: https://gnunet.org/svn/gnunet@32641 140774ce-b5e7-0310-ab8b-a85725594a96
PSYC: some code cleanup

git-svn-id: https://gnunet.org/svn/gnunet@32642 140774ce-b5e7-0310-ab8b-a85725594a96