Raise event from aggregate root

    Entity objects must either extend AggregateRoot or DomainEventProvider.
    Since the usage of Doctrine and/or CRUD plugins requires the use of
    AggregateRoot, there is no ability to call raise() to execute a
    DomainObjectChanged notice. which means that we cannot have event
    handlers listening for onEventOccured.

    Using apply() does not allow us to send DomainObjectChanged objects
    since it would subsequently then require an applyDomainObjectChanged
    method, which is unneeded.

    apply() and raise() do the exact same thing other than the apply()
    method calling $this->executeEvent($event), thus it's a simple matter
    to add raise() to AggregateRoot, which then enables us to do

    $this->raise(new DomainObjectChanged("ChangeEmail", array("email" => $email, "oldEmail" => $this->email)));

    from our Entity objects which extend AggregateRoot so that they can
    use the Doctrine and CRUD plugins.