Double Dragon arcade / MPE private prototype

Original game: Technos Japan, 1987. Original commercial game data is a private
input and is not included in the corresponding-source archive or repository.
The ROM manifest selects the World program with the HD6309 sprite board
(MAME ddragonbl) present in the user's merged ddragonb set.

MAME board and video layout reference, pinned revision:
f8f6b22c3f328b9e0b04ff502989f8536c0d66c0
https://github.com/mamedev/mame/blob/f8f6b22c3f328b9e0b04ff502989f8536c0d66c0/src/mame/technos/ddragon.cpp
https://github.com/mamedev/mame/blob/f8f6b22c3f328b9e0b04ff502989f8536c0d66c0/src/mame/technos/ddragon_v.cpp
BSD-3-Clause. Philip Bennett, Carlos A. Lozano, Rob Rosenbrock, Phil Stroffolino,
Ernesto Corvi, David Haywood and R. Belmont.

MAME 6809 / HD6309 CPU cores: Nathan Woods, Tim Lindner, John Butler, Olivier
Galibert and respective contributors. BSD-3-Clause. Unmodified original
instruction descriptions and helpers are retained in shared/cpu/mame-6x09.
The generated standalone adapter replaces only framework and debugger hooks.

MSM5205 ADPCM decoding and YM2151 pitch reference: Aaron Giles, BSD-3-Clause.
The SID music is an arrangement of the original note stream, not FM synthesis.
Optional original PCM effects require the existing advertised PCM8 service.

MPE package code and Prism+ retain their own notices. See LICENSE.txt and
PRISM-LICENSE.txt. Desktop qualification is not physical hardware acceptance.
