Results 2 issues of Max P.

Many thanks to the author of the Python script! I have implemented the whole thing, with the inspiration of your code, as a small web app, hosted on [Github Pages](https://github.com/PxaMMaxP/bionic-reading-epub-converter-webapp)!...

Fixes #28. The new functions work, but neither the linter runs correctly, nor can I run the tests locally. I'll take another look at this myself in the next few...