Support of Mathjax 2

[GreyWolfling]

Thanks for your extension, it worked fine (I used SimpleMathjax 0.7.4), but some errors have appeared in MW 1.36:

Deprecated: Registering handler for ParserFirstCallInit before MediaWiki bootstrap complete was deprecated in MediaWiki 1.35 [Called from SimpleMathJax::onRegistration in ...\extensions\SimpleMathJax\SimpleMathJax_body.php at line 6] in ...\includes\debug\MWDebug.php on line 376

I tried to install new version 0.8.2, but there is a problem: new version of SimpleMathjax works only with mathjax 3. Mathjax 3 doesn't support some commands (for example the line break(\) is not work).

Is it possible to integrate support of Mathjax 2 in SimpleMathjax 0.8.2? Or may be make some changes in SimpleMathjax 0.7.4 for compatability with MW 1.36?

P.S. I found one issue with local version of Mathjax. I tried to set $wgSmjUseCDN = false; in the LocalSettings.php, but MathJax still loaded from CDN. I changed string №128 in ext.SimpleMathJax.js and MathJax became loading from local copy.

I changed script.src = mw.config.get('wgSmjUseCdn') toscript.src = mw.config.get('wgSmjUseCDN').