SCDoc: remove MathJax support

 - delete all included MathJax files
 - remove `math:` tag from parser
 - remove all references to `math:` tag in SCDoc
SCDoc - MathJax: remove last `math` references and rebuild parser

Thanks to @timblechmann and @lijon for the tip
Merge pull request #910 from gusano/topic/remove_MathJax

SCDoc: remove MathJax support