fix date_i18n problem.

SlimStat use date_i18n Incorrectly,
you most save time with timestamps or Georgian date in database, then show results in date_i18n. which this method that you already have, we lose Timing reference and its not WordPress rule and make conflict.

see this topic:
http://wordpress.org/support/topic/%D9%85%D8%B4%DA%A9%D9%84-%D8%AF%D8%B1-%D8%A7%D9%81%D8%B2%D9%88%D9%86%D9%87-slimstat-%D8%A8%D8%B9%D8%AF-%D8%A7%D8%B2-%D9%86%D8%B5%D8%A8-%D9%86%D8%B3%D8%AE%D9%87-%D8%AC%D8%AF%DB%8C%D8%AF