title: FluentAssertions Should.Equal on collections, containing nulls
body: <p>FluentAssertions seems to fail with NullReferece exception when I try comparing two collections with nulls</p>
  
  <pre><code>    [Test]
      public void DeepWithNulls()
      {
          var l1 = new List&lt;string&gt; { "aaa", null };
          var l2 = new List&lt;string&gt; { "aaa", null };
  
          l1.Should().Equal(l2);
      }
  </code></pre>
  
  <p>Comparison works as expected on collections with no nulls.</p>