[Nice] TURN RFC 5766 support in libnice

[Marcus Lundblad]

Hi.

I have implemented RFC 5766 support in libnice. This means correctly
sending CreatePermission requests for peers the client relays to.
I have also fixed it to send ChannelBind renewals before the 10 min.
timeout comes.

This code can be found in this git repo:

git://github.com/mlundblad/libnice.git

in the master branch

I also plan to eventually fix up TCP relaying to work in RFC mode
(currently it appearantly only supports Google mode).
Perhaps I might look into supporting TLS mode too at some point.

Cheers!

//Marcus