fix assetName used for referenced textures when the parent ldtk is in a nested folder.

Author: jaguire

LDtk/Renderer/LDtkRenderer.cs

@@ -170,7 +170,9 @@ private Texture2D GetTexture(LDtkLevel level, string path)
         else
         {
             string file = Path.ChangeExtension(path, null);
-            return content.Load<Texture2D>(file);
+            string directory = Path.GetDirectoryName(level.WorldFilePath);
+            string assetName = string.IsNullOrEmpty(directory) ? file : $"{directory}/{file}";
+            return content.Load<Texture2D>(assetName);
         }
     }