Since service names are normalized when pulling from the `ServiceManager`, I suggest replacing the array keys

* `zfcuser_user_service`
* `zfcuser_register_form_hydrator`
* `zfcuser_user_hydrator`

with 

* `ZfcUser\Service\User`
* `Zend\Stdlib\Hydrator\ClassMethods`
* `ZfcUser\Mapper\UserHydrator`

On a separate note I think it's a good idea to keep the array of service definition sorted alphabetically (by key).