title: TableView section header in android is blank and clickable
body: <p>I'm using <code>Xamarin.Forms</code>, currently trying to make a <code>TableView</code> without a section header.  Right now on <code>iOS</code> this looks fine as the section header is not visible or clickable, but on <code>Android</code> the header is blank, visible, and clickable.</p>
  
  <p>I've tried this <a href="http://forums.xamarin.com/discussion/18037/tablesection-w-out-header" rel="noreferrer">http://forums.xamarin.com/discussion/18037/tablesection-w-out-header</a></p>
  
  <p>Code in xaml -</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;TableView&gt;
      &lt;TableView.Root&gt;
        &lt;TableSection&gt;
          &lt;TextCell Text="Login" Command="{Binding Login}" /&gt;
          &lt;TextCell Text="Sign Up" Command="{Binding SignUp}" /&gt;
          &lt;TextCell Text="About" Command="{Binding About}"/&gt;
        &lt;/TableSection&gt;
      &lt;/TableView.Root&gt;
    &lt;/TableView&gt;
  </code></pre>
  
  <p>Code in c#</p>
  
  <pre class="lang-cs prettyprint-override"><code>Content = new TableView
  {
      Root = new TableRoot 
      {
          new TableSection () 
          {
              new TextCell { Text="Login", Command = Login }, 
              new TextCell { Text="Sign Up", Command = SignUp },
              new TextCell { Text="About", Command = About },
          },
      },
  };
  </code></pre>