🐛 High memory usage when fed diff of minimized files

Version: 0.1.1

Steps to reproduce:

```
wget https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js -O /tmp/bs-4.4.1.js
wget https://stackpath.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js -O /tmp/bs-4.0.0.js
diff -u /tmp/bs-4.0.0.js /tmp/bs-4.4.1.js | delta
```

Example above seems to use around 8GB and takes 10 seconds to fully display the diff on my system.
