stylecow plugin font-variant

Stylecow plugin to support font-variant properties using font-feature-settings fallback. Inspired by the postcss plugin postcss-font-variant

You write:

p {
	font-variant-ligatures: common-ligatures;
}

And stylecow converts to:

p {
	font-feature-settings: "liga";
	font-variant-ligatures: common-ligatures;
}

More demos in the tests folder