title: Read data content from an URL in a main with Dart
body: <p>In a main(), i would like to read a file from an url. It seams really easy to use the <a href="http://api.dartlang.org/docs/releases/latest/dart_html/HttpRequest.html" rel="noreferrer">HttpRequest from "dart:html"</a> but it's not working from a command line :</p>
  
  <pre class="lang-dart prettyprint-override"><code>import "dart:html" ;
  
  main(){
    String url ="http://foo.bar/foo.txt";
    HttpRequest.getString(url).then((content){
      print(content);
    });
  }
  </code></pre>
  
  <p>=>  The built-in library 'dart:html' is not available on the stand-alone VM.</p>
  
  <p>How can I do it ?</p>