some small errors in quickauth.php

[ivk]

Hi! I think it could be better if your fantastic library will work absolutely properly! I found some errors here, correct it please!

1. Logout method It must be $this->ci->session->sess_destroy(); instead of $this->ci->session->destroy(); at Quickauth.php line#107
2. restrict method (line#234 and more) must be $this->ci->db->where('userid', $userid); (you forget $this-> somethere)
3. #241, must be $user_groups[] = $var['title'];
4. #246, maybe it is better to use redirect($this->login); instead of die(); ?

And thank you very much for your very usefull lib!