Fixed files for creating an account

Fixed tuple creation in users account.
> Fixed case when user type is student OR faculty
> Added default values for borrow limit and waitlist limit on successful
creation of account
> Function checks BOTH username AND email address before creating an
account
> Partial server-side input validation on creating accounts (NOT
considering client-side deletion/modification of source code)
> Improved documentation for administrator.php's create account and
administrator_model.php's insert account