split the document into smaller pieces;
made it standalone by copying antiquote_setup.ML into the repository
added cover page
@manual{isa-imp,
author = {Makarius Wenzel},
title = {The {Isabelle/Isar} Implementation},
institution = {Technische Universit\"at M\"unchen},
note = {\url{http://isabelle.in.tum.de/doc/implementation.pdf}}}