removed little bug in dz and added documentation
removed little bug in dz and added documentation

feltor-dev/feltor,mwiesenberger/feltor,rkube/feltor,mwiesenberger/feltor,rkube/feltor,feltor-dev/feltor,e3reiter/feltor,e3reiter/feltor,e3reiter/feltor,e3reiter/feltor,mwiesenberger/feltor,rkube/feltor,e3reiter/feltor,mwiesenberger/feltor,rkube/feltor,feltor-dev/feltor,rkube/feltor,feltor-dev/feltor