title: UIWebView+AFNetworking issue
body: <p>I use this code:</p>
  
  <pre><code>webView.loadRequest(request!, progress: nil, success: { (responce, html) in
              print("\n\n\nsuccess responce = ", html)
              return html
          }, failure: { (error) in
              print("\n\n\nerror = ", error)
          })
  </code></pre>
  
  <p>But my server has invalid SSL sertificate. So I need to set a security policy. Before I was doing it like that:</p>
  
  <pre><code>[AFHTTPRequestOperationManager manager].securityPolicy.allowInvalidCertificates = YES;
  </code></pre>
  
  <p>But in AFNetworking 3 there is no <code>AFHTTPRequestOperationManager</code> class anymore. How can I set security policy for all requests in AFNetworking 3?</p>