Codechange: introduce SpriteFile to be used by the sprite loader instead of the global FIO slot functionality

src/spriteloader/spriteloader.hpp

@@ -13,6 +13,7 @@
 #include "../core/alloc_type.hpp"
 #include "../core/enum_type.hpp"
 #include "../gfx_type.h"
+#include "sprite_file_type.hpp"
 
 struct Sprite;
 typedef void *AllocatorProc(size_t size);
@@ -73,7 +74,7 @@ public:
 	 * @param load_32bpp  True if 32bpp sprites should be loaded, false for a 8bpp sprite.
 	 * @return Bit mask of the zoom levels successfully loaded or 0 if no sprite could be loaded.
 	 */
-	virtual uint8 LoadSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type, bool load_32bpp) = 0;
+	virtual uint8 LoadSprite(SpriteLoader::Sprite *sprite, SpriteFile &file, size_t file_pos, SpriteType sprite_type, bool load_32bpp) = 0;
 
 	virtual ~SpriteLoader() { }
 };