v0.4.0: graphics settings (F12), FSR 3.1, sharper text and interface

A graphics release, most of it contributed by @Vancete (#8 to #13). Thank you!

• In-game settings on F12 (on a controller: − and + together, then Settings): volume, brightness, contrast,
  saturation and the effects below, applied live and saved to larecomp.ini. LARECOMP_MENU_KEY picks another key
  (Steam takes F12 for screenshots).
• TAA anti-aliasing besides SMAA, and FSR 3.1 upscaling with AMD's presets (Native AA, Quality, Balanced,
  Performance, Ultra Performance). AMD's amd_fidelityfx_vk.dll ships next to the exe; without it, FSR 1.
• Ambient occlusion (SSAO) and indirect light (GI), experimental and off by default.
• Smoother shadows, on by default (the game samples its shadow map without filtering); F12 Shadow filter →
  Game's gives the old look. Better background blur and depth of field in menus and on the title screen, on by
  default (blur_quality = 0 turns it off).
• Sharper text at high resolutions, always on: the game's glyph cache is drawn again at 2x or more (1080p
  fullscreen: 2x).
• Sharper interface (2x), optional: a start-screen button makes the menus' images again at twice their
  resolution from your own game files, with waifu2x (downloaded once from GitHub, 35 MB, checked by its SHA-256).
  About 550 MB in cache/; 90 to 100 s on an RTX 3080. Each image is checked against the original before it is kept.
• Fixes the world drawn wrong after a catch (0.3.2): black trees, bushes with a sign's texture, no dirt path
  until the area changed.

Tested with the zip built for this release, in fresh folders with copies of the game files and saves, without MSYS2
on the PATH: Eevee (FSR 3.1 + TAA + SSAO) and Pikachu (defaults) load a save, reach the world and open the menu. From
the source tree, on both games: every effect on at 30 and 60 fps, 2x text in 1080p fullscreen, and the 2x interface
made and compared on / off. All on NVIDIA (RTX 3080 here, RTX 5070 Ti by @Vancete); not tested on AMD or Intel
GPUs - feedback is welcome in an issue.

Updating from 0.3.x: with the game closed, unzip over your folder (keeps the game files, saves, translations and
settings). The game library is not rebuilt.