Proportion sizing

This is a little bit more code, and adds some simple CSS to the `<head>`, so if its defying all the principals of FitText, feel free to not pull it.

But this is a more better version. It gets the proportion of the size of the item and its font-size, and then uses that to fit into the size of its parent. `.fit-text { display: inline-block; }` helps with getting the right size.

Now we don't have to rely on that hacky compressor value to get the perfect justified sizing.