ext/vorbis/vorbisdec.c: Cleanups. Use refcounting and DEBUG_OBJECT.

ext/vorbis/vorbisdec.c: Cleanups. Use refcounting and DEBUG_OBJECT.

Original commit message from CVS:
* ext/vorbis/vorbisdec.c: (vorbis_get_query_types),
(vorbis_dec_convert), (vorbis_dec_src_query),
(vorbis_dec_sink_query), (vorbis_dec_src_event),
(vorbis_dec_sink_event), (vorbis_handle_identification_packet),
(vorbis_dec_clean_queued), (vorbis_dec_push),
(vorbis_handle_data_packet), (vorbis_dec_change_state):
Cleanups. Use refcounting and DEBUG_OBJECT.
Reset segment on flush, use code methods instead of our
own wrong version.
Fix potential memleak.