Handle namespaces without name

## First fix : Handle namespace without name

Exemple :

```php
namespace {
    class MyGlobalClass() {}
}
```

Ref : http://fr2.php.net/manual/fr/language.namespaces.definitionmultiple.php

## Second fix : handle the case where you affect a new instance to a variable attribute 
```php
$this->$field = new stdClass
```

**Ps :** I have added a test for that two fixes
**Ps 2:** Both cases are present in doctrine/common