title: NSOutLineView with nested NSArray
body: <p>I have nested n level dynamic array, i want to bind it with <code>NSOutlineView</code>,
   but i not getting how to bind it with <code>NSOutlineView</code> using its four delegate methods.</p>
  
  <p>Nested Array like :</p>
  
  <pre><code>(
   {
      id = 3;
      summary = "req 1";
      "sub_requirement" =         
      (
          {
               id = 16;
              "sub_requirement" = "";
              summary = "sub req 1";
          }
      );
  
  },
  { 
      id = 5;
      summary = "req 1-1";
      "sub_requirement" =       
      (
          {
              id = 17;
              "sub_requirement" = "";
              summary = "sub req 1-1";
          },
          {
  
              id = 21;
              "sub_requirement" = "";
              summary = "req 1";
          }
      );
  },
      {
      id = 7;
      summary = "req 1 1";
      "sub_requirement" =         
      (            
          {
              approved = 1;
              budget = 3600;
              description = "";
              estimate = 3600;
              "fk_feature" = 4;
              "fk_parent" = 7;
              "fk_requirementtype" = 1;
              id = 18;
              "sub_requirement" = "";
              summary = "sub req 11";
          }
      );
  
  },
  
  {
      id = 8;
      "sub_requirement" = "";
      summary = "req 1 2";
  },
  
  {
      id = 12;
      "sub_requirement" = "";
      summary = "req 1";
  },
  
  {
      id = 14;
      "sub_requirement" = "";
      summary = req1;
  }
  )
  </code></pre>