Telnetlib3

- bugfix circular reference between transport and protocol, 43 by fried

Telnet client negotiates speed, defaults to 38400. Thanks hughpyle 35

Python 3.7 compatibility (33)

* Fix syntax errors in python 3.7 due to async being a reserved word
* Update tests to use await/async syntax
* drop python3.4 and custom coverage combining
* document 1.0.1 release, project status: seeking new owner :-)

After a year or more of refactoring, we release this new 1.0 API for the telnet protocol. This release prefers the ``shell(reader, writer)`` callback rather than the twisted-style subclassing of ``data_received`` in the previous version.

- bugfix: cannot connect to IPv6 address as client.
- change: TelnetClient.CONNECT_DEFERED class attribute renamed DEFERRED.
Default value changed to 50ms from 100ms.
- change: TelnetClient.waiter renamed to TelnetClient.waiter_closed.
- enhancement: TelnetClient.waiter_connected future added.
- add: functional tests using curl
- add: functional tests piping client and server together

- bugfix: cannot bind to IPv6 address, closes issue 5
- enhancement: Futures waiter_connected, and waiter_closed added to
- server.
- change: TelSh.feed_slc merged into TelSh.feed_byte as slc_function
- keyword.
- change: TelnetServer.CONNECT_DEFERED class attribute renamed DEFERRED.
- Default value changed to 50ms from 100ms.
- enhancement: Default TelnetServer.PROMPT_IMMEDIATELY = False ensures
- prompt is not displayed until negotiation is considered final. It is
- no longer "aggressive".
- enhancement: TelnetServer.pause_writing and resume_writing callback
- wired.
- enhancement: TelSh.pause_writing and resume_writing methods added.