libretro-beetle-pce-fast: Import libretro-beetle-pce-fast-20180720

This package replaces emulators/libretro-mednafen-pce-fast.

Libretro is a simple but powerful development interface that allows for the
easy creation of emulators, games and multimedia applications that can plug
straight into any libretro-compatible frontend. This development interface is
open to others so that they can run these pluggable emulator and game cores
also in their own programs or devices.

Beetle/Mednafen PCE FAST is a NEC TurboGrafx-16/PC Engine/CD video game
system emulator.

(nia)