title: polymer starter kit open url with multi level path
body: <p>In the starter-kit when I run using 'gulp serve' and enter an url with more than one level path for e.g. localhost:5000/register/user then it fails. It basically looks for elements.html in localhost:5000/register/elements/elements.html rather than localhost:5000/elements/elements.html. </p>
  
  <p>However when I open the link by clicking from another page, it works. Any idea how to make this work when I enter the url ?</p>