Have a fallback font for cases where Fabric font download is blocked

[Zlatkovsky]

Suggested in issue OfficeDev/script-lab#426 (comment).
From that issue:

It's due to a common security setting in IE in corporations (not downloading external fonts), so could you include the icons/fonts in question or fall back to another solution for the toolbar in such cases

A quick look online suggests that there are some approaches, such as:
https://stackoverflow.com/questions/23653708/fallback-from-fontawesome-if-font-download-blocked

[Zlatkovsky]

To set expectations, I don't know if it's something we'd get to soon. I also don't know if it's something that Script Lab should do, or the underlying Fabric JS framework that we use (https://github.com/OfficeDev/office-ui-fabric-core).

[bohtho]

@Zlatkovsky Answering questions from #426:
Opening the link/Script lab in regular IE (at my place of work) has the same issues with icons/fonts not showing. Not so in Edge browser, this loads icons/fonts fine it seems.

We do not get office365 accounts, but outlook.com seems to have all icons in buttons in our IE installation.

[Zlatkovsky]

OK, thanks. We'll keep this on the backlog...