0.4.0 - Cheats, special stage fixes, new icon, credits

Cheats, special stage fixes, a new icon, and credits for the community.

• Cheats (Issue #20): OPTIONS > CHEATS has 99 RINGS and SPEED SHOES. These are the codes from Sonic Retro's list whose effect could be confirmed in the game. [Cheats] Codes in Config/chaotix.ini takes any other Action Replay code, such as FFE009:63. Game Genie codes are not supported: they patch the ROM's instructions, and the recompiled code doesn't read them. Achievements and time attack records are not earned while any cheat is on. Details: docs/CHEATS.md.
• Special stages (Issue #21):
  • No more black lines in widescreen. The game frames its 4:3 picture with black sprites, and those are now hidden while the stage is widened.
  • Special stages reached through a giant ring in a level are now widescreen too. That route doesn't change the game mode, so only the level select's special stages had been detected.
• WIDE LOBBY (also #21): a new option in OPTIONS that widens the lobby and the INTRODUCTION Eggman scene as well, for players who prefer widescreen despite those scenes' glitches. Off by default.
• New app icon (Issue #22): pixel-art Knuckles by @Abdouxgo, used for the Windows program, the window and the Android launcher.
• Credits: CREDITS.md now lists everyone who sent code, bug reports and ideas, and it is included in the Windows download.

Thank you to @shinmagus for code, @Abdouxgo for the icon, and @Nickwastakenwastaken, @sloppydoppies, @Pokefan2098, @blueeeLove, @SegaSaturnFan, @datadrivezz, @mechasalesman and @iisonic707ii-spec for their reports and ideas.

Validation: all 26 CTest cases pass on the MinGW build, including the 36,000-frame lockstep and golden-frame runs. The 136 unit tests include tests for cheat codes, for the CHEATS page and for the special stage being recognised in the level's game mode. A ROM test confirms that SPEED SHOES takes Knuckles further and the ring count stays at 99. Special stages entered from a level were tested by switching the game mode back to the level's mid-stage, not through a real giant ring. The packaged Windows build passed the five ROM startup tests with a system-only PATH. The Android APKs have not been tested on a device for this release.

Windows x64 and Android builds are included: arm64-v8a/x86_64 (the usual APK) and armeabi-v7a (32-bit ARM, untested on a device). Both APKs use version code 13 and the same signing certificate as 0.3.9 for in-place updates, debug-signed with Release native code as before.

You must supply your own Knuckles' Chaotix (Japan, USA) ROM. No ROM image or game assets are included.