FORGE-345 Improved the styling for code listings.

The styles of the code listings for the site as well as for the generated PDF have been improved. Upquote handling has been performed for the PDF. Additionally, the line break characters generated in code listing have been suppressed to allow for copy&paste of listings.
Converted the preface section of the book into it's own chapter

This was done to prevent JDF site generation issues, since the upgrade to Awestruct 0.5.2 causes the preface section to be generated without sufficient metadata.