title: How to add a Glyphicon to NavDropdown in ReactBootstrap
body: <p>I'm trying to add a glyphicon to a <code>NavDropdown</code> in React Bootstrap.
  I know that you can add it to a normal <code>Dropdown</code> like this, as explained in the documentation.</p>
  
  <pre><code>&lt;Dropdown id="dropdown-custom-1"&gt;
    &lt;Dropdown.Toggle&gt;
      &lt;Glyphicon glyph="star" /&gt;
      Pow! Zoom!
    &lt;/Dropdown.Toggle&gt;
    &lt;Dropdown.Menu &gt;
      &lt;MenuItem eventKey="1"&gt;Action&lt;/MenuItem&gt;
      &lt;MenuItem eventKey="2"&gt;Another action&lt;/MenuItem&gt;
    &lt;/Dropdown.Menu&gt;
  &lt;/Dropdown&gt;
  </code></pre>
  
  <p><strong>What I've tried:</strong></p>
  
  <p><strong>1. Does not work:</strong></p>
  
  <pre><code>    &lt;NavDropdown eventKey={3} id="basic-nav-dropdown"&gt;
         &lt;NavDropdown.Toggle&gt;
         &lt;Glyphicon glyph="star" /&gt;
         Pow! Zoom!
         &lt;/NavDropdown.Toggle&gt;
         &lt;MenuItem eventKey={3.1}&gt;Action&lt;/MenuItem&gt;
         &lt;MenuItem eventKey={3.2}&gt;Another action&lt;/MenuItem&gt;
      &lt;/NavDropdown&gt;
  </code></pre>
  
  <p><strong>2. Does not work:</strong></p>
  
  <pre><code>    &lt;NavDropdown eventKey={3} title={&lt;Glyphicon glyph="star" /&gt; Dropdown} id="basic-nav-dropdown"&gt;
         &lt;MenuItem eventKey={3.1}&gt;Action&lt;/MenuItem&gt;
         &lt;MenuItem eventKey={3.2}&gt;Another action&lt;/MenuItem&gt;
      &lt;/NavDropdown&gt;
  </code></pre>
  
  <p><strong>3. Does work but the caret is not aligned with the text and it appears in a new line:</strong></p>
  
  <pre><code>    &lt;NavDropdown eventKey={3} title={&lt;div&gt;&lt;Glyphicon glyph="star" /&gt; Dropdown &lt;/div&gt;} id="basic-nav-dropdown"&gt;
         &lt;MenuItem eventKey={3.1}&gt;Action&lt;/MenuItem&gt;
         &lt;MenuItem eventKey={3.2}&gt;Another action&lt;/MenuItem&gt;
      &lt;/NavDropdown&gt;
  </code></pre>