Define text/font properties

Would be fantastic if you could define

```
font-family: local font family name;
font-style: normal;
font-size: 1rem; (or px)
line-height: 1rem; (or px)
letter-spacing: 0rem; (or px)
font-weight: (set to the local font weight names);
```

You alluded to support of this in your Medium article with "You have many text layers, and they need to be the same color as some of your shapes, so you need two types of shared styles. Some text needs be a different size, some need to be center aligned, etc. " but I was unable to get it working successfully.

Thanks! This is an incredible Sketch plugin. :)