Include internet and achievements? #29

Hi, I developed an adapter to add internet and RetroAchievements to the original NES (https://github.com/odelot/nes-ra-adapter).

The software is mature, but we need to improve our PCB design to make it more robust and fit in a cartridge size (today we are using a prototype pcb too big we need to let NES opended).

When I shared in the shmups forum https://shmups.system11.org/viewtopic.php?p=1575761#p1575761 , someone suggest incorporating with one version of opentendo.

I would glad help this initiative.

BTW, great work with opentendo! This is great preservation initiative. Cheers from another NES lover.