Common prefix for reserved class names

If we use a set of reserved class names then it might be an idea to prefix them to indicate their provenance, so e.g.

``` html
⠈⠨⠣⠙⠑⠋⠊⠝⠊⠞⠊⠕⠝⠈⠨⠜
```

would be something along the lines of

``` html
⠈⠨⠣⠙⠑⠋⠊⠝⠊⠞⠊⠕⠝⠈⠨⠜
```

BTW I think "tn" is a very cryptic class name and I think we should strive for names where the meaning is at least somewhat clear. But I'll open a separate issue for that.