Log Message:
gexiv2: update to 0.14.0.

gexiv2 0.14.0 - 18 Sep 2021 (stable)

 * Fix BMFF compile test

gexiv2 0.13.0 - 15 Aug 2021 (development)

 * Enable BMFF support if enabled in exiv2 version
 * Update gexiv2-dump tool
 * Mark gexiv2_metadata_from_stream as deprecated; it is fundamentally broken
 * More additions to API and _try versions that support GErorr if exiv2 might throw
 * Some additions to gexiv2-tool
 * Changes in build configuration