gst-libs/gst/rtp/gstbasertpdepayload.*: Fix for RTPBuffer changes.

gst-libs/gst/rtp/gstbasertpdepayload.*: Fix for RTPBuffer changes.

Original commit message from CVS:
* gst-libs/gst/rtp/gstbasertpdepayload.c:
(gst_base_rtp_depayload_chain),
(gst_base_rtp_depayload_add_to_queue),
(gst_base_rtp_depayload_push),
(gst_base_rtp_depayload_queue_release):
* gst-libs/gst/rtp/gstbasertpdepayload.h:
Fix for RTPBuffer changes.

* gst-libs/gst/rtp/gstrtpbuffer.c: (gst_rtpbuffer_allocate_data),
(gst_rtpbuffer_new_take_data), (gst_rtpbuffer_new_copy_data),
(gst_rtpbuffer_new_allocate), (gst_rtpbuffer_new_allocate_len),
(gst_rtpbuffer_calc_header_len), (gst_rtpbuffer_calc_packet_len),
(gst_rtpbuffer_calc_payload_len), (gst_rtpbuffer_validate_data),
(gst_rtpbuffer_validate), (gst_rtpbuffer_set_packet_len),
(gst_rtpbuffer_get_packet_len), (gst_rtpbuffer_get_version),
(gst_rtpbuffer_set_version), (gst_rtpbuffer_get_padding),
(gst_rtpbuffer_set_padding), (gst_rtpbuffer_pad_to),
(gst_rtpbuffer_get_extension), (gst_rtpbuffer_set_extension),
(gst_rtpbuffer_get_ssrc), (gst_rtpbuffer_set_ssrc),
(gst_rtpbuffer_get_csrc_count), (gst_rtpbuffer_get_csrc),
(gst_rtpbuffer_set_csrc), (gst_rtpbuffer_get_marker),
(gst_rtpbuffer_set_marker), (gst_rtpbuffer_get_payload_type),
(gst_rtpbuffer_set_payload_type), (gst_rtpbuffer_get_seq),
(gst_rtpbuffer_set_seq), (gst_rtpbuffer_get_timestamp),
(gst_rtpbuffer_set_timestamp), (gst_rtpbuffer_get_payload_len),
(gst_rtpbuffer_get_payload):
* gst-libs/gst/rtp/gstrtpbuffer.h:
Don't subclass GstBuffer but add methods and helper functions
to construct and manipulate RTP packets in regular GstBuffers.