Jingle Port Forward

The idea is add a XEP to define TCP and UDP port forwarding in XMPP using Jingle. The same idea of SSH port forwarding. It will permit to share desktop with VNC across NAT's and also SSH access.

The idea is forward ports UDP and TCP directly with UDP and TCP respetively. And also define how to forward UDP over TCP and TCP over UDP to solve some possible firewalls problems.

(DRAFT)