优化一下布局

src/widget/date/calendar/combo.month.date.js

@@ -48,6 +48,7 @@ BI.MonthDateCombo = BI.inherit(BI.Trigger, {
                 el: {
                     type: "bi.vertical",
                     hgap: 6,
+                    vgap: 5,
                     items: [this.popup]
                 }
             }