Adds a nice single-page mode to mdBook by augmenting the print version
Offers a button that navigates to the print version of the given book, with a magic anchor that prompts the userscript to suppress the print window, and makes a best effort to convert sidebar links into anchors. Sidebar links that can't be matched to title IDs are greyed out. In one screenshot you can see the nice little button, and in the other you can see a sidebar link successfully navigating down to the appropriate title.
