v0.2.4 — Colour fixes

Downloads: the same three setup programs; use these instead of the earlier
ones and run the setup again to rebuild the game (and the APK, on Android).

Fixed

• Washed-out colours on Windows (#5): the game asked SDL for its OpenGL ES
  renderer, which on Windows (seen with AMD graphics) can convert every pixel
  as if it were linear light, so the whole picture looked pale. Windows now uses
  SDL's default, Direct3D.
• The game was always at night. The DS clock started at midnight on
  1 January 2000 on every launch, so the overworld always had night lighting.
  It now follows your computer's clock, as on a real DS, including after
  loading a quick save. On an existing save the in-game clock jumps forward to
  today, like a DS that was switched off for a while.