Start and Finish publishing bug fixed for Easytagcloud 2.3

Thanks for the feedback from Federico Lopez Nolasco.

I didn't consider the start publishing and finish publishing data so Easytagcloud tried to index tags from the articles that had not published yet,it would come with a 404 error if the visitor try to open the unpublished ariticles in the related articles page.

Please update your extension if you installed before Nov.25 to avoid the problem.