Add docs for softcover check & clean
Add documentation for KindleGen default & .softcover-build
Scope out customization chapter
Add a stub marketing chapter
Remove marketing from main book
Document build customization
Document deploy customization
Document custom.sty
Edit up to PDF style
Finish first draft of customization chapter
Write the intro & edit
Support Hungarian
Polish the stub PolyTeX chapter
Document and fix overfull hboxes
Fix a broken xref
Make anal changes
Update the example book
Add a second overfull command for xrefs sake