Complete Customer title tests and fix controller
	modified:   core/lib/Thelia/Controller/Api/TitleController.php
	modified:   core/lib/Thelia/Core/Form/Type/CustomerTitleI18nType.php
	modified:   core/lib/Thelia/Model/CustomerTitle.php
	modified:   tests/phpunit/Thelia/Tests/Api/TitleControllerTest.php