This will be the new baseline for master, since, though this change
is a fully API-compatible, one bug fix wrt the alpha value handling
unfortunately would break some unit tests when using an earlier
version.

Change-Id: I5a17ce4085d3311a165748154d107d12b95e2c71
Reviewed-on: https://gerrit.libreoffice.org/49784Reviewed-by: Kohei Yoshida <libreoffice@kohei.us>
Tested-by: Kohei Yoshida <libreoffice@kohei.us>