title: Response header is present in browser but not parsed by Angular $http response.headers()
body: <p>In our Angular app, we need to parse response headers of some $http. </p>
  
  <p>In particular we need to parse some X-prefixed response headers, for example <code>X-Total-Results: 35</code>.</p>
  
  <p>Opening the <code>Network</code> tab of the browser dev tools and inspecting the resource relative to the $http request, I verified that the response header <code>X-Total-Results: 35</code> is present.</p>
  
  <p>in the browser, the X-Total-Results header is available, but cannot be parsed in the Angular $http.</p>
  
  <p>Is there a way to access in $http the 'raw' response and write our custom parser for the header?</p>
  
  <pre><code>$http.({method: 'GET', url: apiUrl,)
      .then( function(response){
          console.log('headers: ', response.headers());
          console.log('results header: ', response.headers('X-Total-Results'));
          // ...
      })
  </code></pre>
  
  <p><strong>console output</strong></p>
  
  <pre><code>headers: Object {cache-control: "no-cache="set-cookie"", content-type: "application/json;charset=utf-8"}
  
  results header: null
  </code></pre>