gst/matroska/matroska-demux.c: Use static pad templates with ANY caps for audio and...

gst/matroska/matroska-demux.c: Use static pad templates with ANY caps for audio and video source pads and get rid of ...

Original commit message from CVS:
* gst/matroska/matroska-demux.c: (gst_matroska_demux_base_init),
(gst_matroska_demux_handle_seek_event),
(gst_matroska_demux_video_caps), (gst_matroska_demux_audio_caps),
(gst_matroska_demux_subtitle_caps),
(gst_matroska_demux_plugin_init):
Use static pad templates with ANY caps for audio and video
source pads and get rid of a lot of unnecessary (and partially
broken) code for the template caps. Clean up caps finding
functions. Fixes playback of audio files/streams that do not
contain the sample rate and/or number of channels in the audio
context (happens a lot with vorbis/mp3 .mka files it seems).
Fixes #337183.
Also add myself to copyright holders.