Add emulator BIOS requirements

[spellboundtriangle]

It would be useful if the emulators page listed information on where to put the BIOS for specific emulators that use or require them, and information or links to information on how to dump them.

I know that a BIOS dump is outright required for FDS games, and some other emulators (GBARunner2, GameYob) use them for greater compatibility or features and such. I'm not sure how you would integrate this information, but it would be helpful for support of using these software.