LaTeXiT 2.7.2

Yes practically `tr` would only be nanoseconds faster, so it's more a matter of style.

30/40 of current `gsub` usages are of the `gsub('.', ...` variety, where `tr` would suffice. The other 10 only seem to substitute one occurrence of their Regexp, so `sub` would suffice. So `gsub` is never actually necessary.

Perhaps using `gsub` consistently as a catch-all may be more familiar for maintainers who aren't so familiar with Ruby though. Not sure how much of a concern that is since it's a relatively rare and more advanced usage in casks.