CodetableItem 增加无参构造器，解决序列化报错的问题

src/main/java/com/brilliance/mda/runtime/mda/CodetableItem.java

@@ -13,6 +13,8 @@ public class CodetableItem
         this.description = description;
     }
 
+    public CodetableItem(){}
+
     public CodetableItem(String label, String value)
     {
         this.label = label;