v2.2.1 with Symfony Validator v2.2.1

Updated Validator components from both frameworks to latest stable versions.

```JSON
{
  "require": {
    "php": ">=5.3.3",
    "symfony/validator": "v2.2.1",
    "zendframework/zend-validator": "2.1.*"
  }
}
```

Tagged as 2.2.1, PHPUnit tests OK.