[WIP] integrate Stack\Builder

This is a PoC integrating [stack](http://stackphp.com/) in Thelia.

A new tag is created : stack_middleware

If you want to add a new middleware in stack, your class must implement the HttpKernelInterface and had a constructor with at least 1 argument, the app's HttpKernel.

Here is a simple example : 

Class : 

```
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpKernel\HttpKernelInterface;

class Test implements HttpKernelInterface
{
/**
     * @var \Symfony\Component\HttpKernel\HttpKernelInterface
     */
    protected $app;

    public function __construct(HttpKernelInterface $app)
    {
        $this->app = $app;
    }

    public function handle(Request $request, $type = self::MASTER_REQUEST, $catch = true)
    {
        return $this->app->handle($request, $type, $catch);
    }
}
```

and the service definition

```
<service id="stack.test" class="TestStack\Stack\Test">
    <tag name="stack_middleware" priority="100"/>
</service>
```

Here a more complete example. For our middleware, we need the event dispatcher : 

```
use Symfony\Component\EventDispatcher\EventDispatcherInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpKernel\HttpKernelInterface;


/**
 * Class TestServices
 * @package TestStack\Stack
 * @author manuel raynaud <mraynaud@openstudio.fr>
 */
class TestServices implements HttpKernelInterface
{
    protected $app;

    protected $dispatcher;

    public function __construct(HttpKernelInterface $app, EventDispatcherInterface $dispatcher)
    {
        $this->app = $app;
        $this->dispatcher = $dispatcher;
    }


    public function handle(Request $request, $type = self::MASTER_REQUEST, $catch = true)
    {
        $this->dispatcher('event_name', new Event());
        return $this->app->handle($request, $type, $catch);
    }
}
```

and the service definition : 

```
<service id="stack.services" class="TestStack\Stack\TestServices">
    <argument type="service" id="event_dispatcher" />
    <tag name="stack_middleware" priority="100"/>
</service>
```