title: Error handler in Observable is not mapped to JSON
body: <p>Error callback in subscribe is not mapped to JSON trough map function! Why? </p>
  
  <pre><code>this.http.get("/something")
              .map((response: any) =&gt; response.json())
              .subscribe((response: any) =&gt; {
                    // response is body of request
              }, (error: any) =&gt; {
                  // error must be mapped again
                  let error = JSON.parse(error._body);
              });
  </code></pre>