Chapter with broken images can't be rendered

[troyeguo]

When zip.js trys to uncompress these broken images, it will throw header error. But foliate.js doesn't properly catch these error which aborts the whole rendering process.

How to reproduce:

1. Import this book in https://johnfactotum.github.io/foliate-js/reader.html
2. Click Chapter 1 Probability

[johnfactotum]

Perhaps one should just catch this in the loadBlob function and return an empty Blob (or even a custom placeholder image, if you're feeling fancy)?