Auth Class: Manage accounts and authenticate users

This class can manage accounts and authenticate users.

It can perform several types of operations to manage the records of users stored in a MySQL database (accessed using the MySQLi extension) like creating user accounts, activate accounts, change the user e-mail address or the password, and remove accounts.

The class can also authenticate an user with a given password, create user sessions, delete sessions, get the session information, check if the session is valid, manage failed login attempts.