Plotter: open figs in browser

Let's add an option in Plotter to automatically launch figures in browser, esp. when ran from Jupyter.

This would be complementary to 'show' option which calls fig.show() method which displays the figure in the notebook, and 'html' option which saves a html file but does not open it.

This is helpful for very large plots that are not automatically fitted to the notebook's width (editor's window, e.g., VSCode's) and are nasty to scroll through.