Merge remote-tracking branch 'dpvc/v2.2-beta' into v2.2-beta
Merge branch 'v2.2-beta' of https://github.com/dpvc/MathJax into v2.2-beta
Merge branch 'v2.2-beta' of https://github.com/dpvc/MathJax into v2.2-beta
Merge branch 'v2.2-beta'

This brings master up to date for v2.2-latest.
Merge remote-tracking branch 'mathjax/master' into develop