Allows several translation files for same domain / locale 

For exemple : 

Translator config 

```php
//Add Zend translations files for validator (Zend_Validate & Zend_Captcha)
'translation_files' => array(        	
	array(
		'type' => 'phparray',
		'filename' =>  getcwd().'/vendor/zendframework/zendframework/resources/languages/en/Zend_Validate.php',
		'locale'  => 'en_US',
		'text_domain' => 'validator'
	),        	
	array(
		'type' => 'phparray',
		'filename' =>  getcwd().'/vendor/zendframework/zendframework/resources/languages/en/Zend_Captcha.php',
		'locale'  => 'en_US',
		'text_domain' => 'validator'
	)
)
```