utf8 language not supported for categories text

[parsa25eng]

Hi. I have used your package for a utf8 language. For categories, it is not supported to assign utf8 text. I have investigate the package code and finally find out that in the "JsTransformerPresenter.php" file and for "encode_x_axis()" function, "JSON_UNESCAPED_UNICODE" must be used for "json_encode" function. I will so grateful if you fix this issue as soon as possible. Thanks.