virtual-group支持layouts对象

src/base/combination/group.virtual.js

@@ -44,8 +44,8 @@ BI.VirtualGroup = BI.inherit(BI.Widget, {
     },
 
     _packageLayout: function (items) {
-        var o = this.options, layout = BI.deepClone(o.layouts[0]);
-
+        var o = this.options, layouts = BI.isArray(o.layouts) ? o.layouts : [o.layouts];
+        var layout = BI.deepClone(layouts[0]);
         var lay = BI.formatEL(layout).el;
         while (lay && lay.items && !BI.isEmpty(lay.items)) {
             lay = BI.formatEL(lay.items[0]).el;
@@ -113,4 +113,4 @@ BI.VirtualGroup = BI.inherit(BI.Widget, {
 });
 BI.VirtualGroup.EVENT_CHANGE = "EVENT_CHANGE";
 
-BI.shortcut("bi.virtual_group", BI.VirtualGroup);
+BI.shortcut("bi.virtual_group", BI.VirtualGroup);