title: Window title is overwritten when using Caliburn's conductor<object> in view model
body: <p>New to Caliburn and WPF MVVM, so I may be overlooking something pretty simple and I couldn't find anything searching the web. </p>
  
  <p>Set up a simple wpf project with Caliburn.Micro. Set window title in ShellView.xaml. Works fine. Main MetroWindow displays the title as expcted.</p>
  
  <p>Works fine:</p>
  
  <pre><code>[Export(typeof (IShell))]
  public class ShellViewModel : PropertyChangedBased, IShell
  {}
  </code></pre>
  
  <p>But change to:</p>
  
  <pre><code>[Export(typeof (IShell))]
  public class ShellViewModel : Conductor&lt;object&gt;
  {}
  </code></pre>
  
  <p>and Window title is the fully qualified name of this ViewModel. ANy help would be appreciated. Thanks.</p>