mixpanel tracking on all pages

 On branch master

	modified:   website/_content/1-about/page.md
	modified:   website/_content/3-books/page.md
	modified:   website/_themes/pinfinity/layouts/default.html
	modified:   website/_themes/pinfinity/partials/foot-javascript.html
	modified:   website/_themes/pinfinity/partials/head-javascript.html
	modified:   website/_themes/pinfinity/templates/book.html