title: "Include" extension method does not work with LinqKit
body: <p>I have 2 classes:</p>
  
  <pre><code>public class Employee
  {
      public int Id {get;set;}
      public string Name {get;set;}
  }
  
  public class Remuneration
  {
      public int Id {get;set;}
      public Employee Employee {get;set;}
      public int Amount {get;set;}
  }
  </code></pre>
  
  <p>The normal query:</p>
  
  <pre><code>return _context.Remunerations.Include("Employee")
  </code></pre>
  
  <p>works perfect</p>
  
  <p>But when I am using Albahari's LinqKit and giving the query as below:</p>
  
  <pre><code>return _context.Remunerations.AsExpandable().Include("Employee")
  </code></pre>
  
  <p>It does not give any error there.</p>
  
  <p><strong>But does not include the Employee data in the result</strong>.</p>