fix variout memory leaks

src/twn_textures.c

@@ -60,6 +60,7 @@ SDL_Surface *textures_load_surface(const char *path) {
 
     int width, height, channels;
     void *image_mem = stbi_load_from_callbacks(&callbacks, &context, &width, &height, &channels, 0);
+    SDL_FreeRW(handle);
     if (!image_mem)
         goto ERR_CANNOT_READ_IMAGE;