DDC-1955 - @EntityListeners

http://www.doctrine-project.org/jira/browse/DDC-1955

Hi.

This path adds support for ```@EntityListeners```

This path add another way to handle events
allow configure the same listener for many specific entities.
And give the EventArg in the current lifecycle callback system.

Usage :

```php
<?php
/**
 * @EntityListeners({"ContractListener"})
 * @HasLifecycleCallbacks
 * @Entity  
 */
class Contract
{
    /** @PostLoad */
    public function postLoadHandler(LifecycleEventArgs $event)
    {
        // do something
    }
}
class ContractListener
{
    /** @PrePersist  */
    public function prePersistHandler(Contract $contract)
    {
        // do something
    }
    /**
     * @PostPersist
     * Most of cases just the entity is needed.
     * as a second parameter LifecycleEventArgs allow access to the entity manager.
     */
    public function postPersistHandler(Contract $contract, LifecycleEventArgs $args)
    {
        // do something
    }
}
```