Pop stepper visualisation out into a floating dialog

[psychemedia]

To provide more real estate for the stepper visualisation, it might be useful to pop the stepper visualation out into a floating JQuery dialog widget.

As a proof of concept, if we find the div id for (the div has class nbtutor-canvas) we can pop it out into its own window if we have jquery and jquery-ui loaded using the following:

%%HTML
<script>$( "#SPECIFIC_ID" ).dialog()</script>

Peeking at the code, the corresponding div appears to be defined here: https://github.com/lgpage/nbtutor/blob/07798a044cf6e1fd4eaac2afddeef3e13348dbcd/src/es6/notebook/notebook.es6#L49