avfilter/lut3d: support slice threading.
mpegts muxer: DVB subtitles multiple languages support

* restore multiple languages data from extradata to PMT table
* setting correctly hearing empaired subtitling type

Reviewed-by: Marton Balint <cus@passwd.hu>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/mpegtsenc: Check data array size in mpegts_write_pmt()

Prevents out of array writes

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avfilter/curves: support slice threading.