Add is_registered() and is_activated() functions.
Convert tabs to spaces.
Add is_reset() function.
The strength of password encryption is now configurable.
Replace the call to and existence of check_duplicate_user() with is_registered().
Check if the user has already requested a password reset before generating and sending a new $random_hash.
Another email can still be sent, but it will have the same hash as the first one.
Fix bug where delete_user() doesn't verify the password parameter correcty.
Fix bug where login() does not read the $encryption_rounds setting.
Send another email if a user tries to create_user() multiple times, instead of returning FALSE.
Cleanup unused variables in the login() function.