header for transport validation monitoring API


git-svn-id: https://gnunet.org/svn/gnunet@31918 140774ce-b5e7-0310-ab8b-a85725594a96
transport validation monitoring API (not yet complete) + CLI
+ fix for crash in transport/plugin_transport_udp.c


git-svn-id: https://gnunet.org/svn/gnunet@31919 140774ce-b5e7-0310-ab8b-a85725594a96