(output): add comments to lp-book latex output.
##
LATEX: {
- OUTPUT: r'''{
-\parindent 0pt
-\catcode`\@=12
-\ifx\preLilyPondExample \undefined
- \relax
-\else
- \preLilyPondExample
-\fi
-\def\lilypondbook{}
-\input %(base)s-systems.tex
-\ifx\postLilyPondExample \undefined
- \relax
-\else
- \postLilyPondExample
-\fi
+ OUTPUT: r'''{%%
+\parindent 0pt%%
+\catcode`\@=12%%
+\ifx\preLilyPondExample \undefined%%
+ \relax%%
+\else%%
+ \preLilyPondExample%%
+\fi%%
+\def\lilypondbook{}%%
+\input %(base)s-systems.tex%%
+\ifx\postLilyPondExample \undefined%%
+ \relax%%
+\else%%
+ \postLilyPondExample%%
+\fi%%
}''',
PRINTFILENAME: '''\\texttt{%(filename)s}