title: React-Bootstrap - How to activate a Tab outside NavItem
body: <p>I want to change tab without clicking on the NavItem evtKey="x"</p>
  
  <p>If I have a TabContainer like this :</p>
  
  <pre><code>      &lt;Tab.Container id="tabcontainer" defaultActiveKey="a"&gt;
            &lt;Tab.Content animation&gt;
              &lt;Tab.Pane eventKey="a"&gt;
                &lt;ComponentA /&gt;
              &lt;/Tab.Pane&gt;
              &lt;Tab.Pane eventKey="b"&gt;
                &lt;Componentb /&gt;
              &lt;/Tab.Pane&gt;
            &lt;/Tab.Content&gt;
            &lt;Nav stacked bsStyle="pills" pullLeft&gt;
               ... NavItems ...
            &lt;/Nav&gt;
        &lt;Tab.Container&gt;
  </code></pre>
  
  <p>I want to know how I can do this :</p>
  
  <pre><code>    eventHandler(){
         changeToTab("b")
      }
  </code></pre>
  
  <p>inside ComponentA.</p>