Format the notes in a book format.

This changed sections to chapters and subsections to sections.  There are a few hard-coded references to theorem numbers, etc., that should be checked.  Also, commented out is a template for the license statement.

Dana: if you want to do cc-by-sa, you can get the image that is commented out from here: https://github.com/jasongrout/multivariable-calculus-IBL/blob/master/by-sa.pdf.  Otherwise, you can get other cc images from the CC website.