Update tornado/zmq/ioloop to latest stable

The current code depends on version locking of the tornado package and others to avoid a major refactor of its event loop. The latest version of these packages have indeed deprecated the APIs used in the current code.

As pipenv is somewhat lacking in terms of version locking, there's a high chance that we will end up with nasty bugs soon if we don't clean that up. See ioloop mentions in the tornado release notes.