Add Sameboy core (GB) to RALibretro

[kdecks]

This is a missing core with achievement support in an effort to bring all cores that support achievements in Retroarch into RALibretro.

[Jamiras]

This core crashes when loading a game in RALibRetro

[Jamiras]

The core seems to working now, but there's some odd static in the sound - RALibretro doesn't appear to like the fact that it's sending us 384KHz audio. Easily noticeable using Final Fantasy Legends (GB).