- update message types


git-svn-id: https://gnunet.org/svn/gnunet@30913 140774ce-b5e7-0310-ab8b-a85725594a96
- revamp mesh_common code, minor refactoring


git-svn-id: https://gnunet.org/svn/gnunet@30914 140774ce-b5e7-0310-ab8b-a85725594a96