mpegtsmux: mux private data streams

Submitted by Martijn Grendelman

Link to original bug (#673582)

Description

Mpegtsdemux is capable of demuxing private data streams, like subtitles and teletext, but mpegtsmux is not capable of muxing them. So, if you want to transcode a TS, but keep all non-audio/video streams as-is, this is not possible.

This is a request to add private data stream support to mpegtsmux.