The editors/openoffice-4 port currently depends on textproc/saxon-devel and
relies on features that are only present in this version of saxon. The
recent update to math/scilab added a dependency to textproc/saxon-he, and
it requires features that are only present in this version. Unfortunately
saxon-devel and saxon-he conflict because they both want to install
/usr/local/share/java/classes/saxon9-xqj.jar, which means that openoffice-4
and scilab can't both be installed on the same machine. Avoid this problem
by tweaking openoffice-4 use a private copy of saxon. This requires a
new version of the ext_sources tarball.

Bump PORTREVISION so that users pick up the updated port.

Modernize MASTER_SITES syntax and update MASTER_SITE for unowinreg.dll.

Update comment to take de facto mainternship.

PR: 193776
Differential Revision: https://reviews.freebsd.org/D1553
Reviewed by: bapt, pfg
Approved by: mat (mentor)