Multiple produce/consume in single annotation

Currently multiple definitions of consume/produce MIME types must be defined like this:

``` php
/**
 * @Consume(text/plain)
 * @Consume(application/json)
 */
public function muliple_consume($data) { /* ... */ }
```

This issue suggest them to be defines as:

``` php
/**
 * @Consume({text/plain,application/json})
 */
public function muliple_consume($data) { /* ... */ }
```

with same result.
