[MOD] removed unused back-pointing keys in iscsi


git-svn-id: https://svn.uni-konstanz.de/disy/Treetank/trunk/treetank@7539 e3ddb328-5bfe-0310-b762-aafcbcbd2528
[MV] node to data classes


git-svn-id: https://svn.uni-konstanz.de/disy/Treetank/trunk/treetank@7540 e3ddb328-5bfe-0310-b762-aafcbcbd2528
Merge remote-tracking branch 'refs/remotes/git-svn'