ext/mad/: Add id3demuxbin (which is a simple bin consisting of id3demux and typefind...

ext/mad/: Add id3demuxbin (which is a simple bin consisting of id3demux and typefind), take over rank from id3demux, ...

Original commit message from CVS:
* ext/mad/Makefile.am:
* ext/mad/gstid3demuxbin.c: (gst_id3demux_bin_get_type),
(gst_id3demux_bin_base_init), (gst_id3demux_bin_class_init),
(gst_id3demux_bin_init), (gst_id3demux_bin_remove_pad),
(found_type), (gst_id3demux_bin_change_state):
* ext/mad/gstid3tag.c: (gst_id3_tag_add_src_pad),
(gst_id3_tag_init), (gst_id3_tag_handle_event),
(gst_id3_tag_src_link), (gst_id3_tag_chain),
(gst_id3_tag_change_state), (plugin_init):
* ext/mad/gstmad.h:
Add id3demuxbin (which is a simple bin consisting of id3demux
and typefind), take over rank from id3demux, remove typefind
code from id3demux. Makes all broken mp3s that I know of work,
and thereby fixes #152688.