moved structure Keyword to OuterKeyword (Isar/outer_keyword.ML);
support for tagged commands;
tuned theory presentation interface;
\index{model checking example|(}%
\index{lfp@{\texttt{lfp}}!applications of|see{CTL}}
\input{CTL/document/Base.tex}
\input{CTL/document/PDL.tex}
\input{CTL/document/CTL.tex}
\index{model checking example|)}