Replace it with a handler function passed to `jupyter-ioloop-start`.
* jupyter-ioloop-comm.el: Do it.
* jupyter-channel-ioloop-comm.el: Do it.
* jupyter-channel-ioloop-comm.el: Do it.
* jupyter-ioloop.el: Do it. Update comments and doc.
(jupyter-ioloop--delete-process): Remove. It was used to perform
cleanup when the object used for dispatching to a handler method was
garbage collected. Since we no longer rely on having an object for
dispatching, preferring just a function to call, its not needed.
(jupyter-ioloop--make-filter): Fall back to calling handler function
instead of `jupyter-ioloop-handler`. Only handle ioloop start/stop
events internally. This means we can remove the check for those in
`jupyter-ioloop-comm`.
* test/jupyter-test.el: Update tests to take into account above
changes.
Having the `jupyter-comm-layer` abstraction means we do not need to do so.
* jupyter-base.el (zmq): Un-require.
(jupyter-socket-types): Move to `jupyter-channels.el`.
(jupyter-session): Don't mention zmq in doc string.
(jupyter-available-local-ports, jupyter-make-ssh-tunnel): New functions.
(jupyter-tunnel-connection): Use them.
* jupyter-channel-ioloop-comm.el: New file.
* jupyter-channels.el (jupyter-messages): Un-require.
(jupyter-comm-layer, zmq): New requires.
(jupyter-socket-types): Moved from `jupyter-base.el`.
(jupyter-send, jupyter-recv):
Implementations for `jupyter-session` moved from `jupyter-messages.el`.
(jupyter-sync-channel-comm): `jupyter-comm-layer` implementation for
`jupyter-sync-channel` objects moved from `jupyter-comm-layer.el`.
* jupyter-comm-layer.el (jupyter-channel-ioloop): Un-require.
(jupyter-sync-channel-comm): Move implementation to `jupyter-channels.el`.
(jupyter-ioloop-comm): Move implementation to new file `jupyter-ioloop-comm.el`.
(jupyter-channel-ioloop-comm):
Move implementation to new file `jupyter-channel-ioloop-comm.el`.
* jupyter-ioloop-comm.el: New file.
* jupyter-ioloop.el (zmq): Require.
* jupyter-kernel-manager.el
(jupyter-make-client): Ensure `jupyter-channel-ioloop-comm` is required.
* jupyter-messages.el (jupyter-send)
(jupyter-recv): Moved to `jupyter-channels.el`
* jupyter-repl.el
(jupyter-connect-repl): Ensure `jupyter-channel-ioloop-comm` is required.
* test/jupyter-test.el (jupyter-available-local-ports): New test.
* test/test-helper.el (jupyter-channel-ioloop-comm): New require.
