- support for more use cases (fix #72).
- `serialize_response` and `serialize_request` and `serialize` call signature changed.
- `serialize_response` and `serialize_request` names are left for compatibility,
it is better to use `params_serializer` and `response_serializer` instead.
- Removed unnecessary dependencies.
- Tests completely rewritten.
- Decorating will only be done if necessary, which will positively affect performance.
