ext/: Added query/convert/formats functions to vorbis and theora decoders so that the outside world can use them too....

Original commit message from CVS:
* ext/theora/theoradec.c: (gst_theora_dec_init),
(theora_get_formats), (theora_get_event_masks),
(theora_get_query_types), (theora_dec_src_convert),
(theora_dec_sink_convert), (theora_dec_src_query),
(theora_dec_src_event), (theora_dec_event), (theora_dec_chain):
* ext/vorbis/vorbisdec.c: (vorbis_dec_get_formats),
(vorbis_get_event_masks), (vorbis_get_query_types),
(gst_vorbis_dec_init), (vorbis_dec_convert),
(vorbis_dec_src_query), (vorbis_dec_src_event), (vorbis_dec_event):
Added query/convert/formats functions to vorbis and theora decoders
so that the outside world can use them too. Fixed seeking on an
ogg/theora/vorbis file by disabling the seeking on the
theora srcpad.