adding functionality to support dynamic valueOption attributes

A feature of ZF2 form elements with valueOptions is being able to set attributes on a valueOption
```
$select=new \Zend\Form\Element\Select('test');
$select->setValueOptions(
    [
        ['attributes'=>['data-key'=>'value'],'value'=>'myValue','label'=>'myLabel']
    ]

    );

echo $this->formselect($select);
```
the element view helper returns HTML:
```
<select name="test"><option value="myValue" data-key="value">myLabel</option></select>
```
Being able to add these attributes to options is extremely useful for passing additional values for front-end processing, like adding a boolean value for an objects status,etc.

The attributes would be defined as :
```
$os->setOptions([
            'object_manager' => $odm,
            'target_class' => 'BsImmoManager\Domain\Aggregate\Advertiser',
            'property' => 'name',
            'option_attributes' => [
            [ 'data-type'=>'getType']
            ],
            'find_method' => [
                'name' => 'findAll',
                'params' => []
           ]
        ]);
```
Whereby the key option_attributes accepts an array of key/values, the keys are already filtered in ZF2 but typically include data-, aria-,onEvent, etc. The value is a method which will be called on the object which is cast to a string and used for the option attribute value.

```
data-key="value"
```