Grab the MathJaX support PR from the blackfriday repo

[kaushalmodi]

Hello,

Can you please merge this PR: russross/blackfriday#412

It's a shame that such good PR's were ignored in the original repo without any comments or feedback.

PS: I assume you know the trick to merge any PR.. just add https://github.com/Vonng/blackfriday as a remote, and merge those commits from the v2 branch.

Copying the original author: @Vonng

[kaushalmodi]

Wow! Thanks for this quick merge!

[kaushalmodi]

@kjk BTW I wonder why you didn't credit the original author in that commit. The right way would be to set the original author as the commit author and yourself as only the commiter.

[kjk]

This wasn't a merge. The code diverged enough that I had to manually port it. And I don't speak advanced git.

[kaushalmodi]

I don't speak advanced git.

If it were me, I'd learn enough git so that I retain the original authorship. That way, the original authors don't feel discouraged or cheated. Then you can have additional commits of your own tweaking that commit... Just something to note for future.