Another fix to get pdf on release build to work (#232)

Adding page numbers to pdf by changing to latex pdf builder (#224)

* Adding line numbers to pdf

Just a test for now

* Update _toc.yml

* switch pdf build to latex

* Update _toc.yml

* Update requirements.txt

* Update build_book.yml

* Update requirements.txt

* Update build_book.yml

* Update build_book.yml

* Update build_book.yml

* Update build_book.yml

* clean up

* Update _toc.yml

* Update _config.yml