gst/udp/: Use NetBuffer and small cleanups.

gst/udp/: Use NetBuffer and small cleanups.

Original commit message from CVS:
* gst/udp/Makefile.am:
* gst/udp/gstmultiudpsink.c: (gst_multiudpsink_get_type),
(gst_multiudpsink_base_init), (gst_multiudpsink_class_init),
(gst_multiudpsink_init), (gst_multiudpsink_finalize),
(gst_multiudpsink_get_times), (gst_multiudpsink_render),
(gst_multiudpsink_set_property), (gst_multiudpsink_init_send),
(gst_multiudpsink_add), (client_compare), (free_client),
(gst_multiudpsink_remove), (gst_multiudpsink_clear),
(gst_multiudpsink_get_stats):
* gst/udp/gstudpsrc.c: (gst_udpsrc_get_type),
(gst_udpsrc_base_init), (gst_udpsrc_class_init),
(gst_udpsrc_create), (gst_udpsrc_set_uri), (gst_udpsrc_start),
(gst_udpsrc_unlock), (gst_udpsrc_stop):
Use NetBuffer and small cleanups.
Implement client removal in multiudpsink.