有货币详细页面加入loading效果. code review by LZF

-var $ = require('jquery');
+var $ = require('jquery'),
+    loading = require('../plugin/loading');
 var page = 1;
 
+loading.showLoadingMask();
+
 function ajaxCurrencyDetail(page) {
     $.ajax({
         type: 'POST',
@@ -29,3 +32,5 @@ $(window).scroll(function() {
 });
 
 ajaxCurrencyDetail(page);
+
+$(document).ready(loading.hideLoadingMask);