and expand out the bit-tricks some of the code was playing to make it
more obvious what is going on

Change-Id: I9c98334393b939b1d900425f6133556ce88247ae
Reviewed-on: https://gerrit.libreoffice.org/29734Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>