Added collapsed blocks with output where useful, minor amendments

• Added collaped code blocks with expected Git output where necessary.
• Set autclrf = true in Git setup
• Added deliberate error of not ending files with a newline, explain it
• Create all files with echo.> ... to avoid problems with extensions
• Explain how to navigate in Git's pager
• Moved directory css into src
• Minor wording fixes
• Fixes README, link slides PDF

Fixes #2 (closed).