bundle-bundle bundle

The bundle bundle bundle bundle bundle... implements a sort of a
composer based autoloader for required bundles. The idea behind
this is that graviton-*-bundles will use this to autoregister
themselves in AppKernel and routing.

This would look something like this:

## composer.json
````javascript
{
   "extras": {
     "graviton-config-import": true,
     "graviton-routing-import": true
   }
}
````

## src/Graviton/AcmeBundle/GravitonAcmeBundle.php
````php
<?php
namespace Graviton\AcmeBundle\;

use Symfony\Component\HttpKernel\Bundle\Bundle;
use Graviton\BundleBundle\GravitonBundleInterface;

class GravitonAcmeBundle extends Bundle implements GravitonBundleInterface
{
    public function getBundles()
    {
        return array(
            new \Graviton\AcmeTestBundle\GravitonAcmeTestBundle()
        );
    }
}
````