[Users] client_nat_test

[Andreas Granig]

Dan Pascu wrote:
> The point of that duplicated code there is to not have to load both 
> modules at the same time.
> 
> Besides that, they don't do _exactly_ the same thing at all. 

Ok, but why not merging the advantages of the two versions into one 
module? That way, people don't have to wonder which of the functions to use.

And I'd also vote for splitting it up into three modules, like Ovidiu 
Sas proposed in another mail, namely an rtpproxy and mediaproxy 
controller module and a separate nathelper module.

Just my 2 cents,
Andy