smtp_client: rename self -> client (descriptive)
Merge pull request #727 from msimerson/smtp_client4

smtp_client: rename self -> client (descriptive)
first whack, needs work
new method get_listen_addrs() from createServer()
add express to package.json
moved get_listen_addrs() into listen_${prot}_

methods
refactored get_smtp_server out of

setup_smtp_listeners.
not clean, but works for Express routes and wss
post-rebase merge