title: Programmatically navigate using React router
body: <p>With <code>react-router</code> I can use the <code>Link</code> element to create links which are natively handled by react router. </p>
  
  <p>I see internally it calls <code>this.context.transitionTo(...)</code>.</p>
  
  <p>I want to do a navigation. Not from a link, but from a dropdown selection (as an example). How can I do this in code? What is <code>this.context</code>? </p>
  
  <p>I saw the <code>Navigation</code> mixin, but can I do this without <code>mixins</code>?</p>