Removed and replaced cores

TODO other recent non-wbox->wbox conversions

This is not an exhaustive list; some cores that were in development, but were never available in a release before being scrapped, are not included.

(A78) EMU7800

Removed in 2.2.1. Present in 1.x backports through 1.13.2.

Outdated Waterboxed port replaced with up-to-date Waterboxed port after 2.9.1. It was then wired up for SMS/GG.

Our Libretro core adapter was rewritten in 2.9.

A non-Waterboxed melonDS port was replaced with a from-scratch (and Waterboxed) port in 2.7.

Removed in 2.0. Present in 1.x backports through 1.13.2.

The SGB core based on SameBoy was removed in 2.7. A Game Boy / Color core based on SameBoy was added in 2.8.