Icons not rendered in ipywidgets

[blois]

From: #60 (comment)

Icons for buttons are not rendered in colab. I'd love to see this supported.

An empty button is showed for the following code:

my_button = widgets.Button(icon="home")
display(my_button)

I believe this is because IPyWidgets reference FontAwesome but do not include it.

Example which does render:

from IPython.display import HTML
my_button = widgets.Button(icon="home")

display(HTML('''<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css"> '''))
display(my_button)

[ybressler]

Clever workaround @blois.

[tylere]

This is also affecting the caret icons used in the Accordion widget.

Repo notebook: https://colab.sandbox.google.com/gist/tylere/4fe5346907af9ac5ffd69f08cc669def/accordian-widget-test.ipynb