Broken links from the book to the repository

[Yamboy1]

It appears that at some point, the folder names in this repo wre changed to remove spaces, but some of the links in the book weren't updated for this, leading to broken links.

One other thought I had, it would be nice if there was a link from every page to the repo folder for that page, only a few pages have links.

[Kinaetron]

@Yamboy1 So I've decided to pick up the work on the book, so I'II investiage this