Generic Type on Raw Query response

It would be great to have a generic type on database.query() method, passing a T generic to the ArrayCursor class.

Example:
``` 
 query<T = any>(query: AqlQuery, options?: QueryOptions): Promise<ArrayCursor<T>>;
```

I will send a PR with this feature, typescript types will be useful on raw queries, because it currently returns **any** type on every raw query.