Release v0.12.1

Changed

• Did not bump the supported version of Spelunky, this still works only with 1.25.0b
• Relaxed some speedrun mode rules to align with some stuff that has recently been allowed.
• Move only known .lvl files to Data/Levels

Added

• Added udjat_wall_heads as an entity sheet.
• Option disable_steam_achievements to disable receiving any achievements.
• Option use_playunky_save to create a separate save file from the vanilla game and use that instead. Potentially overridden by allow_save_game_mods or block_save_game.
• Composable shader mods via #extends, check the Wiki for more details.
• Sprite sheet customization via e.g. _col.png images.

Fixed

• Crash on shutdown
• Issue with sprite conversion when mods use unexpected casing in folder structure