This patch splits osmo_rtp_parse in two functions:
osmo_rtp_get_hdr
osmo_rtp_get_payload
So we can validate corrent RTP header to access its fields. Then,
obtain the payload.
This patch adds the initial RTP support for libosmo-netif, it's based
on Harald's RTP support available in openBSC.
I have also added a couple of example to show how our new channel
infrastructure interacts with the RTP layer.
Signed-off-by: Pablo Neira Ayuso <pablo@gnumonks.org>