Added tag 0.4.0 for changeset d00923a04e30

bump version to 0.4.0

upgrade to tokio 1.0

remove use of tokio::prelude

fix version number in README

Added tag 0.3.0 for changeset fc0da3927a59

bump version

rename spawn_async_*() to spawn_*() to follow upstream changes

add function to borrow underlying protocol wrapper

minimize trait requirements of Client<C>

reimplement protocol function as wrapper object

preindent protocol functions

leverage impl trait at argument position

move unix-specific Client code to dedicated module

remove deprecated type aliases

use crate:: to import crate-local modules

rewrite examples

rewrite Client by using async/await

rewrite run_command() by using async/await

redefine UiHandler by using async-trait