gst/playback/: Add support for chained ogg files. Prepare for playlist support. This...

gst/playback/: Add support for chained ogg files. Prepare for playlist support. This patch introduces the concept of ...

Original commit message from CVS:
* gst/playback/gstdecodebin.c: (unlinked):
* gst/playback/gstplay-marshal.list:
* gst/playback/gstplaybasebin.c: (gst_play_base_bin_class_init),
(gst_play_base_bin_init), (group_create), (get_active_group),
(get_building_group), (group_destroy), (group_commit),
(queue_overrun), (remove_groups), (add_stream), (unknown_type),
(add_element_stream), (no_more_pads), (probe_triggered),
(preroll_unlinked), (new_decoded_pad), (removed_decoded_pad),
(state_change), (setup_source), (gst_play_base_bin_get_property),
(gst_play_base_bin_change_state), (gst_play_base_bin_add_element),
(gst_play_base_bin_link_stream),
(gst_play_base_bin_get_streaminfo):
* gst/playback/gstplaybasebin.h:
* gst/playback/gstplaybin.c: (gst_play_bin_class_init),
(remove_sinks), (setup_sinks), (gst_play_bin_change_state):
Add support for chained ogg files. Prepare for playlist
support. This patch introduces the concept of pad groups, which
together compose one playable media file.