[DDC-2042] Added "targetEntity" to AssociationOverride

Hey,

I needed to override "targetEntity" so I forked Doctrine and applyed it myself. Just after that I found a Ticket [DDC-2042] in your Jira so I added a unit test to and would be more than happy to see this commit get merged in to the main master (at some point ;)).

Cheers, Alex

I will stick around in the #doctrine-dev on Freenode for any questions. My nick there is "fanta".

Keep up the good work.

/**
 * @ORM\Entity
 * @ORM\Table(name="customer")
 * @ORM\AssociationOverrides({
 *      @ORM\AssociationOverride(name="products",
 *          targetEntity="MyNewProduct"
 *      )
 * })
 */