Original commit message from CVS:
Reviewed by: Tim-Philipp Müller  <tim at centricular dot net>
* gst/matroska/matroska-demux.c: (gst_matroska_demux_init_stream),
(gst_matroska_demux_parse_info),
(gst_matroska_demux_parse_blockgroup_or_simpleblock),
(gst_matroska_demux_parse_cluster):
* gst/matroska/matroska-ids.h:
* gst/matroska/matroska-mux.c: (gst_matroska_mux_class_init),
(gst_matroska_mux_init), (gst_matroska_mux_start),
(gst_matroska_mux_create_buffer_header),
(gst_matroska_mux_write_data), (gst_matroska_mux_set_property),
(gst_matroska_mux_get_property):
* gst/matroska/matroska-mux.h:
Add SimpleBlock support to matroska demuxer and muxer (part of
Matroska v2). (#319731)