Initialize Mathematica language

Language initialization can cause error when done after executing
`\FV@FormattingPrep` command from `fancyvrb` package. This can happen
inside `\mmaInlineCell`, if it's used without previous language
initialization.

Proper initialization happens e.g. inside `mmaCell` environment so it's
easy to miss this problem.

To fix it, we simply initialize language inside package.

mmacells.sty

@@ -825,6 +825,12 @@
   morekeywords={_},
   keywordsprefix=_, % Blank... patterns with head
 }[keywords,comments,strings,fancyvrb]
+
+% Use newly defined Mathematica language to make sure everything is properly
+% initialized. \lstset sets options only inside current group,
+% delimited by braces, so this has no effect besides initialization.
+{\lstset{language=[base]Mathematica}}
+
 \lstdefinestyle{MathematicaFrontEnd}{
   showstringspaces=false,
   columns=fullflexible,