v0.1-alpha

First test version. It has been tried on the Pico Plus 2 board only, where the game
still runs slower than intended; see the README for what has been tested.

• Runs Diablo with the shareware data (spawn.mpq) or the full game (DIABDAT.MPQ) on
  the Adafruit Fruit Jam and on a Pimoroni Pico Plus 2 with the Adafruit DVI and microSD
  breakouts.
• 640×480 picture over HDMI, music and sound over HDMI or the headphone jack.
• USB keyboard, mouse and gamepads; NES and SNES controllers and the SNES Mouse on the
  PicoNES PCB; the Wii Classic Controller on the Fruit Jam.
• Every button of Xbox, PlayStation, SNES and NES controllers has a function in the
  game, including the stick clicks. On a NES controller, Select gives access to spells
  and potions.
• Graphics and sounds are copied to the board's flash memory the first time they are
  needed, so later loads are faster.
• Saved games are compatible with DevilutionX 1.5.5 on a PC.
• Can also be started from the menu of
  pico-bootLoader, where it is
  listed as Diablo among the Ports.
• The board runs at 384 MHz. At this clock the picture has no dots or lines on TVs and
  monitors that show them at 378 MHz, and the USB port of the Pico Plus 2 board keeps
  working. Thanks to @szuping for the hint that led to this.