Netplay support

[lwcorp]

I'm aware https://fceux.com/web/download.html states "there are no plans to fix [netplay] at this time". However, https://fceux.com/web/help/NetworkPlay.html still gives hope "this issue will be resolved in a future release."

I figured I might as well show support for it here. I think it's a major part in preservation of this game console, and Nestopia UE for example did seemingly manage to pull it off.

[Chipsum]

Mesen also managed it well, I hope Fceux will too.