Macro for returning the file system URL to a File or Image Asset, identified by it’s assetId.

      #-------------------------------------------------------------------

       process ( assetId, returnFileName )

       returns the file system URL if url is the URL for an Asset in the system that has storageId and filename
       properties.  If no Asset with that URL exists, then an internationalized error message will be returned.

       assetId

       The URL to the Asset.

       returnFileName

       If returnFileName is defined the macro will return only the File Name instead of a url.