title: Unable to create Rx.Observable from JS event
body: <p>I'm trying to figure out how to use <a href="https://github.com/Reactive-Extensions/RxJS" rel="nofollow">rx.js</a> with a dog-simple example, but can't figure out what reference or file I'm missing that means it isn't working.</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
  &lt;head&gt;
      &lt;title&gt;Empty&lt;/title&gt;
      &lt;script src="/Scripts/rx.js"&gt;&lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;script&gt;
          var thing = Rx.Observable.fromEvent(document, 'keydown');
      &lt;/script&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>That's literally it. The script line correctly loads a local copy of rx.js 2.4.1 freshly downloaded from nuget.</p>
  
  <p>I'm getting the error Rx.Observable.fromEvent is not a function, so I'm assuming that there is a missing reference.</p>
  
  <p>It might just be the time of night, but I'm struggling to see what I'm doing wrong. Any help?</p>