mpegtemux/demux: support "interlaced" JPEG 2000 stream

Submitted by Aaron Boxer

Link to original bug (#785225)

Description

According to spec, interlaced mode specifies two J2K code streams placed in a single PES packet.

See https://bugzilla.gnome.org/show_bug.cgi?id=753323 for more details.

We should support muxing an interlaced signal into this format, rather than treating it as progressive as we currently do.

Also demuxing a stream in this format.