Original commit message from CVS:
* gst/rtp/gstrtpmp4gpay.c: (gst_rtp_mp4g_pay_class_init),
(gst_rtp_mp4g_pay_init), (gst_rtp_mp4g_pay_parse_audio_config),
(gst_rtp_mp4g_pay_parse_video_config), (gst_rtp_mp4g_pay_new_caps),
(gst_rtp_mp4g_pay_setcaps), (gst_rtp_mp4g_pay_flush):
* gst/rtp/gstrtpmp4gpay.h:
Make more things work.
Handle ACC config strings.