title: How to check observableArray change
body: <p>I am using knockout_2.0.js. I have an observableArray on which i set subscribe. Like :</p>
  
  <pre><code> var Items = ko.observableArray();
  
  
   Items.subscribe(function(newValue){
  
    //I want to check here whether the item is Added or Deleted from the array
  
   }); 
  </code></pre>
  
  <p>How can i do this ?</p>