Repair the data set deleter

This is a fix of the data set deleter.
Fix 1: When deleting the data without the meta data the data set object is not deleted. Otherwise you will not be able to delete the meta data of the data set.
Fix 2: the values are deleted when the data set is deleted.
Fix 3: the coupled ontology terms are removed from the database;
Fix 4: the Category LUT are removed when deleting the meta data of a data set.

Info: It is functional not possible to delete the referential data (individual data and the Mref data) only based on meta data  because they are coupled to the data and not to the meta data.