Split the introduction chapter in two

[DamienIrving]

Most of the current introduction chapter is about course details (the big picture, license, audience, syllabus, acknowledgements, dedications). This content needs to be moved into a numberless prologue (perhaps called "Overview" or "Welcome"), along with a new "how to use this book" section (see below) and some text on how to contribute to the book.

Chapter 1 (which we might rename "Getting Started" or something) should then just contain the initial course content. That includes the existing Project Structure content and possibly also the software installation and data download instructions currently in Appendix E and Section 1.2.1.

How to use this book

Our suggestions on "how to use this book" could be as simple as -- "Work through each chapter, following along with the commands and changes described in the text. Try at least half of the exercises for each chapter" -- to something as complex as an appendix with suggestions for a suggested course plan, adapting these materials to a lecture, finding a mentor or someone to help you (if doing self-study), etc.

Other notes from the reviewer (@ChristinaLK) include:

• Emphasizing the presence of exercises and solutions, as well as recommendations for how to use them. I agree with the decision to include the exercises at the end of each chapter, but I think a note recommending that readers not wait until the end to check out some of the available exercises would be a good idea.

• Outlining the standard chapter format: introduction, content, exercises; identifying the callout box format as a mechanism to supplement the main flow of text.

Cleaning up appendices

Once the new prologue is complete, we should be able to remove appendices A, B and C. See this discussion for details.

[gvwilson]

@lwjohnst86 can you please do this one, since it involves figuring out how to unnumbered preface sections in Bookdown?

[lwjohnst86]

Sounds good.