ext/ogg/: Ported ogg muxer.

ext/ogg/: Ported ogg muxer.

Original commit message from CVS:
* ext/ogg/Makefile.am:
* ext/ogg/README:
* ext/ogg/gstoggdemux.c: (gst_ogg_pad_typefind),
(gst_ogg_pad_submit_packet), (gst_ogg_demux_sink_activate),
(gst_ogg_print):
* ext/ogg/gstoggmux.c: (gst_ogg_mux_init),
(gst_ogg_mux_request_new_pad), (gst_ogg_mux_next_buffer),
(gst_ogg_mux_push_page), (gst_ogg_mux_queue_pads),
(gst_ogg_mux_get_headers), (gst_ogg_mux_set_header_on_caps),
(gst_ogg_mux_send_headers), (gst_ogg_mux_collected),
(gst_ogg_mux_change_state):
Ported ogg muxer.