Log message:
tex-gentium-sil{,-doc}: add version 6.200

This is a redistribution of the original Gentium release from
SIL, not altered in any way. Gentium is a typeface family
designed to enable the diverse ethnic groups around the world
who use the Latin, Cyrillic and Greek scripts to produce
readable, high-quality publications. The Gentium family
includes a complete Greek font, supporting both monotonic and
polytonic forms. While some Greek characters do closely
resemble Latin ones, it is a separate design that embraces the
robust, distinctive character of the Greek script, but does so
within the design context of the whole typeface. As a result,
the two scripts can be successfully mixed in a paragraph or
page of text.