Collab with Normalize-OpenType.css

Hey! Thanks for the shout-out in the README. I maintain Normalize-OpenType.css.

If you are thinking of incorperating any features, let me know. I’d be happy to help. I have also been using and contributing very small pieces to [Typogr.js](https://github.com/ekalinin/typogr.js) for a while which is in a very similar space. Perhaps having a consensus on a class name or tag between all three for small caps would be a start.

I have been partial to using `abbr` tags for small caps, but I can understand the appeal of just using `.caps` or `.small-caps`.

I would also recommend dropping the ligature support, these can be handled entirely with CSS now. My understanding is that _fi_ and _fl_ as a single glyph are kind of a deprecated or frowned-upon part of Unicode, since OpenType and `font-feature-settings` takes care of that now while preserving the _f_, _l_, and _i_ as separate characters.

Let me know what you think! Nice job on the library so far, always nice to find other people that care this much about this stuff.