Faceball 2000 16-Player Link Cable support

[Proletar666]

Support for the 16-player adapter; the situation with this unreleased accessory is described here:

https://www.reddit.com/r/Gameboy/comments/a9kmbz/comment/ecke10k/

DoubleCherryGB emulator reverse-enginereed the accesory:

https://www.reddit.com/r/emulation/comments/1b1kadg/doublecherrygb_16_player_faceball_2000_emulation/

Since GBE+ aims at emulating accessories, I think it falls within the emulator's scope. Would be cool to see supported in GBE+.

[shonumi]

Since I've finished with all the officially licensed Game Boy peripherals, I do have time to add some unreleased accessories like this and others (Alleyway Vaus controller, WorkBoy, Sakura Taisen TV Adapter), eventually. I believe these items belong in the project since they would have been official had they been released, and there's licensed games/software that still have code for them. Just note that I still have no plans for any unofficial 3rd party peripherals though.

Might be a while before I take a look at the Daisy-Chain Link Cable adapter for FaceBall 2000 though, since other stuff is in the pipeline for GBE+ at the moment.