Almond initialization bug

[eric-czech]

I found that if you start a notebook on a fresh kernel, create a plot, run the same cell again to recreate the same plot, and then refresh the page without restarting the kernel, the plot will no longer render. More importantly, this means that if you ever rerun whatever plot you created first then it won't render anywhere else (like nbviewer) even though the plots are still rendering well in the notebook/page you've created them with.

This seems to be because the call to Almond.init is happening under the scenes when the first plot is generated but then the plotly JS dependency definition is lost on a rerun of the same plot. Do you think there Is there a better way to do that? The two best solutions I can think of are to either force that call to be explicit (like plotly-python) or make sure that caveat is documented well.

Happy to work on a PR one way or the other for it.