use listings environment for code listings
remove \ in aliascon arguments
introduce \cs command to markup latex command sequences
better treat htonly, texonly, and discard environments

- rename \htonly...\endhtonly to \begin{htonly} ... \end{htonly}
- discard environment in LaTeX via \usepackage{verbatim}
move hyphenation to fricas.sty
remove \simpleCaption
\protect\axiom... in \caption
remove obsolete \ttraggedright
make page a bit wider