title: Angular2 to REST WebApi CORS issue
body: <p>I'm using an angular2 front end and WebApi backend.
  The webapi is CORS enabled</p>
  
  <pre><code>var cors = new EnableCorsAttribute("*", "*", "*");
  GlobalConfiguration.Configuration.EnableCors(cors);
  </code></pre>
  
  <p>and it works, because I have different sites (jQuery/Javascript) that use this api.  But with angular2 it doesn't.  I get the following message:</p>
  
  <blockquote>
    <p>Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.</p>
  </blockquote>
  
  <p>Maybe is something related to "preflight request" ?</p>