libx265: Bump version requirement

Build 13 has a crucial fix which makes x265_encode_headers work
as its always been documented.

Previous to this, the check was incorrect.

Also allows for use of the repeat headers flag.

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>
libx265: Use the repeat headers flag when not using global headers

This allows proper muxing and seeking in things like MPEG-TS, by
placing headers by random access points.

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>