Union: Replaces the existing region with the union of the existing and new regions.
Exclude: Replaces the existing region with the part of itself that is not in the new
region.
Complement: Replaces the existing region with the part of the new region that is not
in the existing region.

Change-Id: Iabbe0ddfa082a332e94dd85b6444b234d1bdee35
Reviewed-on: https://gerrit.libreoffice.org/44380Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Bartosz Kosiorek <gang65@poczta.onet.pl>