Example file autogenerated by Mathematica.
Added a simple Mathematica package as a test case.
Added languages and regenerated samples.json.
Added text-only lexer, since Pygments doesn't support Mathematica.
Added another Mathematica sample, improving accuracy.
merge master; regen samples
please the pedant
Merge pull request #1081 from github/pr-931-updated

Mathematica (part deux) -- replaces #931