gst/rtp/: Added simple generic mpeg4 depayloader.

gst/rtp/: Added simple generic mpeg4 depayloader.

Original commit message from CVS:
* gst/rtp/Makefile.am:
* gst/rtp/gstrtp.c: (plugin_init):
* gst/rtp/gstrtpmp4gdepay.c: (gst_rtp_mp4g_depay_base_init),
(gst_rtp_mp4g_depay_class_init), (gst_rtp_mp4g_depay_init),
(gst_rtp_mp4g_depay_setcaps), (gst_rtp_mp4g_depay_process),
(gst_rtp_mp4g_depay_set_property),
(gst_rtp_mp4g_depay_get_property),
(gst_rtp_mp4g_depay_change_state),
(gst_rtp_mp4g_depay_plugin_init):
* gst/rtp/gstrtpmp4gdepay.h:
* gst/rtp/gstrtpmp4gpay.c: (gst_rtp_mp4g_pay_class_init),
(gst_rtp_mp4g_pay_parse_audio_config), (gst_rtp_mp4g_pay_setcaps),
(gst_rtp_mp4g_pay_flush):
Added simple generic mpeg4 depayloader.
Fix generic mpeg4 payloader.