Draft asyncio API

1. Support the following basic data communications use cases with asyncio semantics (awaitable operations):

Sending data

• sending WS-Discovery SOAPEnvelope message objects as defined in the generic base daemon
• sending WS-Discovery UDP messsage objects with support for unicast, multicast, retrying etc.

Receiving data

• receiving WS-Discovery SOAPEnvelope message objects as defined in the generic base daemon

Support additional use cases for integrating WS-Discovery into asyncio-based applications

• TBD