title: Router` no longer defaults the history prop to hash history
body: <p>Using React-Router in ES5, I have the below code</p>
  
  <pre><code>var React = require('react');
  var Render = require('react-dom').render;
  var Router = require('react-router').Router;
  var Route = require('react-router').Route;
  var hashHistory = Router.hashHistory;
  var browserHistory = Router.browserHistory;
  
  var About = require('./components/about/aboutPage');
  
  var routes = (
      &lt;Router&gt;
          &lt;Route path="/" handler={App}&gt;
              &lt;Route path="about" handler={About}/&gt;
          &lt;/Route&gt;
    &lt;/Router&gt;
  );
  
  module.exports = routes;
  </code></pre>
  
  <p>This is rendered in {main.j} as </p>
  
  <pre><code>var ReactDOM = require('react-dom');
  var Router = require('react-router').Router;
  var routes = require('./routes');
  
  ReactDOM.render(&lt;Router&gt;{routes}&lt;/Router&gt;, document.getElementById('app'));
  </code></pre>
  
  <p>However, in the console, am getting this warning and nothing loads up:</p>
  
  <pre><code>bundle.js:1845 Warning: [react-router] `Router` no longer defaults the history prop to hash history. Please use the `hashHistory` singleton instead
  </code></pre>
  
  <p>I have clearly passed {hashHistory} in the code above, but still it keeps on complaining.</p>
  
  <p>Any hints on what could be going wrong?</p>
  
  <p>Thanks</p>