Styles with external refernece

Please make it possible that the a DES / CDR file can refer to an external CDSS / CDT file. So styles can be maintained centrally and are always up to date in the DES files.

So a large number of DES / CDR can be adapted centrally.

Possibly it would be good to be able to set whether the CDSS / CDT can be changed from a DES / CDR and whether changes in the CDSS are immediately effective in all DES / CDR.