Initial version.
Merged in changes from development repository:

   This version works.  Added fields to the `gwirdsif.Irods_Objects' and
   `gwirdsif.Dublin_Core_Metadata' database tables and data members to the corresponding
   classes.  These fields and data members are used to create cross-references between the
   objects.

   Previously, it was possible to extract information about the relationship between objects
   by using the handles, but it makes it easier to have this information stored in the tables
   mentioned above.

   The next step is to use this information in the function |purge_dc_metadata|.