modified with last changes

Modified to make it working with last changes.

Some points : 

- If you delete the db in the `setUp` method of your test, don't forget to reload data before wanting to match some nodes

- The response now returns always a Response object, so maybe for some methods it is more convenient to do : 
```
$client->getLabels();
$labels = $client->getBody();
```

- no more need to add the array('graph') in the cypher queries