This is useful in scripts or places where there is no asyncio
event loop running.

This may sometimes happen with IPyparallel clients if they
cannot connect to the scheduler.

Also move the plotting functionality out of the learner itself,
as there can be more than 1 way to plot a given learner.

This information is already in '_scale'. We can always add this
back in as a property later.

Also add an example notebook that shows the learner running and
updating a live plot.