Added $options['label_generator']. A \Closure can be given to set a label with multi property values like 'label_generator' => function($entity) { return $entity->getOne().' - '.$entity->getTwo();}
Test fixes and CS fixes for the proxy form element callable-based label
Adding upgrade notes
CS fixes, removing fluid interface
CS fixes
Merge pull request #219 from doctrine/feature/multi-property-labels

Added `$options['label_generator']` to the proxy form element