reCAPTCHA integration

to use recaptcha in aauth set 'recaptcha_active' to true 
define 'recaptcha_login_attempts' (default = 4) 
define 'recaptcha_siteKey' and 'recaptcha_secret' from https://www.google.com/recaptcha/admin

place generate_recaptcha_field() in your login form

if the 'recaptcha_login_attempts' is reached the recaptcha appears through generate_recaptcha_field()