A diff tool that provides line and token level colorization.

Based on the [Patience Diff
algorithm](https://bramcohen.livejournal.com/73318.html) described by Bram
Cohen and then expanded upon by James Coglan in two blogs posts
([algorithm](https://blog.jcoglan.com/2017/09/19/the-patience-diff-algorithm/)
and
[implementation](https://blog.jcoglan.com/2017/09/28/implementing-patience-diff/)).
# FAQ
## Why?
Cause I wanted a learning project and this seemed like a reasonable one.
## Did you learn anything interesting?
The way that token level diffing uses the same algorithm as the line level
diffing is pretty cool in my mind. I didn't think going into it that I would
structure it that way and it all kinda just fell out.