CC-5727 : History search range using incorrect timezone offset (also Nowplaying)

sending the timestamp string back for nowplaying as well.
added error class to history page if end is < start.

airtime_mvc/public/js/airtime/showbuilder/main_builder.js

@@ -46,7 +46,8 @@ AIRTIME = (function(AIRTIME) {
         showLeadingZero: false,
         defaultTime: '0:00',
         hourText: $.i18n._("Hour"),
-        minuteText: $.i18n._("Minute")
+        minuteText: $.i18n._("Minute"),
+        onClose: validateTimeRange
     };
     
     function setWidgetSize() {