gst/rtp/: Add theora pay/depayloaders.

gst/rtp/: Add theora pay/depayloaders.

Original commit message from CVS:
* gst/rtp/Makefile.am:
* gst/rtp/gstrtp.c: (plugin_init):
* gst/rtp/gstrtptheoradepay.c: (gst_rtp_theora_depay_base_init),
(gst_rtp_theora_depay_class_init), (gst_rtp_theora_depay_init),
(gst_rtp_theora_depay_finalize),
(gst_rtp_theora_depay_parse_configuration),
(gst_rtp_theora_depay_setcaps),
(gst_rtp_theora_depay_switch_codebook),
(gst_rtp_theora_depay_process),
(gst_rtp_theora_depay_set_property),
(gst_rtp_theora_depay_get_property),
(gst_rtp_theora_depay_change_state),
(gst_rtp_theora_depay_plugin_init):
* gst/rtp/gstrtptheoradepay.h:
* gst/rtp/gstrtptheorapay.c: (gst_rtp_theora_pay_base_init),
(gst_rtp_theora_pay_class_init), (gst_rtp_theora_pay_init),
(gst_rtp_theora_pay_setcaps), (gst_rtp_theora_pay_reset_packet),
(gst_rtp_theora_pay_init_packet),
(gst_rtp_theora_pay_flush_packet),
(gst_rtp_theora_pay_finish_headers), (gst_rtp_theora_pay_parse_id),
(gst_rtp_theora_pay_handle_buffer),
(gst_rtp_theora_pay_plugin_init):
* gst/rtp/gstrtptheorapay.h:
Add theora pay/depayloaders.