Bug: Validation bypassed when POST is empty

I have a validator set up for one of my resources. `label` is a required field, `street` is optional. However, when I send an empty POST request, it completely ignores my validation rules, and passes the request to the controller. I end up with an MySQL error `Integrity constraint violation: 1048 Column 'label' cannot be null`

```
'Api\\V1\\Rest\\Address\\Validator' => array(
         array(
                'name' => 'street',
                'required' => false,
                'filters' => array(),
                'validators' => array(
                    0 => array(
                        'name' => 'Application\\Validator\\Text',
                        'options' => array(
                            'multiline' => false
                        ),
                    ),
                ),
                'description' => 'street name',
                'allow_empty' => true,
                'continue_if_empty' => true,
            ),
            array(
                'name' => 'label',
                'required' => true,
                'filters' => array(),
                'validators' => array(
                    array(
                        'name' => 'Application\\Validator\\Text',
                        'options' => array(
                            'multiline' => false
                        ),
                    ),
                ),
                'allow_empty' => false,
                'continue_if_empty' => false,
            )
     )
```

With httpie:
`http POST http://localhost/address`