Moved spritesheet texture handling to anm2 instead of resources; added undoing for spritesheet texture changes; refactoring

src/resources.h

@@ -10,10 +10,7 @@ struct Resources
 {
     GLuint shaders[SHADER_COUNT];
     Texture atlas;
-    std::map<s32, Texture> textures;
 };
 
 void resources_init(Resources* self);
-void resources_texture_init(Resources* self, const std::string& path, s32 id);
 void resources_free(Resources* self);
-void resources_textures_free(Resources* self);