/socklisten has a -p switch for upnp.
Upnp can fail for various reasons, I would like to be able to know if upnp failed when using /socklisten -p (if listening was successful in itself), for example $sock().upnp could return 'ok','fail' or $null if -p wasn't used or if it's not a listening socket, depending on if the upnp part was successful or not.
I'd like to be able to use upnp with /sockudp as well, /sockudp -p.
