[GH-423] DDC-1955 - @EntityListeners

This issue is created automatically through a Github pull request on behalf of FabioBatSilva:

Url: https://github.com/doctrine/doctrine2/pull/423

Message:

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 }

  }
  ```