No support for nested url parameters

[ChristophP]

When trying to set a nested url parameter the [] are percent encoded.

url.setQueryParam('content[id]', 'test') // sets content%5Bid%5D=test```

The solution would be to extend `setQueryParam` to allow a third parameter to customize nesting behavior, like the native node module `querystring` does https://nodejs.org/api/querystring.html#querystring_querystring_stringify_obj_sep_eq_options