Recaptcha

So I added the reCaptcha feature to the login screen now it requires to have 3 config variables: 

```
$cfg['Servers'][$i]['captchaLogin'] = true;
$cfg['captchaLoginPublicKey'] = "6LcrzOASAAAAAM0ygRAj9FOf7Wh4rqlLPcMsrDPU";
$cfg['captchaLoginPrivateKey'] = "6LcrzOASAAAAAA8cw2-s9Rz-GARJlayUBZGcMzmG";
```

Because of the Content Security Policy it didn't quite work on Chrome until I found a way to put www.google.com to the safe list in the headers. Can you take a look at this and if you have any other solution I would like to hear it. 

Also I need to know how do we know if the user is logged in or not? What I need exactly is on AuthenticationCookie.class file, line 376 I need a way to check after the submit is pressed and the data is processed I need to dismiss the case when the user has entered correct info and captcha code. Because currently if I return false on that line 376, after correct info and captcha the user will be logged in but returned to that login screen again because CAPTCHA input fields are empty. I hope I made myself clear, if not please let me know and I will try to explain the problem better.