Fixed date constructor issue for FF & IE
Fixed date constructor issue for FF & IE

https://github.com/najlepsiwebdesigner/foundation-datepicker/issues/20
arnkorty/foundation-datepicker,najlepsiwebdesigner/foundation-datepicker,suitedJK/foundation-datepicker,BeudyZlip/foundation-datepicker,najlepsiwebdesigner/foundation-datepicker,arnkorty/foundation-datepicker,suitedJK/foundation-datepicker,Sopamo/foundation-datepicker,Sopamo/foundation-datepicker,BeudyZlip/foundation-datepicker