1.6/develop

Hi, I made a simple change that I thought it will be good to add.
I'm developing a project in FuelPHP and to increase even more the safety of PBKDF2 I added a simple bit of code that allows the developers to change the auth iterations number!

Thanks!

PS I'm new to git and github. Did I make this in the right way?
PPS You may find some errors in my spelling but I'm not a native english speaker. I'm portuguese.