title: Create a list from two object lists with linq
body: <p>I have the following situation</p>
  
  <pre><code>class Person
  {
      string Name;
      int Value;
      int Change;
  }
  
  List&lt;Person&gt; list1;
  List&lt;Person&gt; list2;
  </code></pre>
  
  <p>I need to combine the 2 lists into a new <code>List&lt;Person&gt;</code>
  in case it's the same person the combine record would have that name, value of the person in list2, change would be the value of list2 - the value of list1.
  Change is 0 if no duplicate</p>