title: MVC 4 Bundle - unable to bundle content e.g. css/javascript outside MVC project content folder
body: <p>For an MVC 4 project, I have a requirement to include/bundle content files that reside outside the MVC project e.g. somewhere in a CDN.</p>
  
  <p>This works:</p>
  
  <pre><code>bundles.Add(new StyleBundle("~/Content/css").Include("~/Content/Css/site.css"));
  </code></pre>
  
  <p>This does not work:</p>
  
  <pre><code>bundles.Add(newStyleBundle("~/Content/css").Include("D:/Media/Styles/Css/site.css"));
  </code></pre>
  
  <p>The error I get is:</p>
  
  <blockquote>
    <p>The URL 'D:/Media/Styles/Css/site.css' is not valid. Only application
    relative URLs (~/url) are allowed. Parameter name: virtualPaths</p>
  </blockquote>
  
  <p>In short, is it at all possible to have asset files residing outside the project's Content folder, for example when using a CDN? if so, what is the best approach?</p>