as part of cleaning up the use of the non-const-ref returning methods.
i.e. methods like
   long& X()

And make the classes final.

Change-Id: Ice0aa1932124e77f5ed672b527c2a092ec80c481
Reviewed-on: https://gerrit.libreoffice.org/49475Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>