Jsonrpcclient

- Pass response_expected to send_message. Lets clients know if a response is
expected from the request. Certain socket clients can use this to not listen
for a response.

- Returned the convenience functions, request, notify and send.
- Clean up response.py.

- Add a socket client.
- Fixed missing import in async_client.py.

- response.data will _never_ be None. For single requests it's _always_ a
JSONRPCResponse, for batch requests it's _always_ a list.
- Raise ReceivedErrorResponse exception on receving a JSON-RPC error
response. This won't affect too many who are using HTTP, since an
exception is already raised when a non-2xx error response is returned.
- Removed ParseResponseError, the json.JSONDecodeError is clear enough.

- Optionally pass an SSLContext to AiohttpClient. This client now requires
aiohttp 3+.

_The 3.x releases will support Python 3.5+ only._

- Remove the config module. Add new params to configure the client. (46)
- Remove the `*_server.py` files, which were deprecated. (79)
- Rename aiohttpClient to AiohttpClient.
- Include http status code and reason in aiohttp log entries.
- Remove headers from http_client's log entries, they weren't used.
- Update the Tornado client to subclass AsyncClient. (44)
- Remove HTTPClient.last_request and last_response, they weren't used. (27)
- Remove ReceivedErrorResponse.
- HTTP clients raise an exception on non-2xx status code response. (67)
- Remove zmq_client module, use zeromq_client instead. (84)
- Move all client modules into a `clients` subpackage. Import from
jsonrpcclient.clients. (83)
- Change code to python 3 style: remove future and past.builtins. Change super
calls to just super(). Change basestring to str. (71)
- Remove jsonrpcclient.Request and Notification. Import
jsonrpcclient.request.Request and Notification instead.
- Remove jsonrpcclient.request. Import jsonrpcclient.clients.http_client.request instead.
- Remove the need for requests library to be installed, if not using it. (85)
- Add type hints (92)
- Log to the debug log level (not info).
- Add support for configuration files.
- Remove the convenience functions (request and notify).
- Remove zeromq-async client.
- Configure logging pythonically.