MathJax.isPacked and MathJax.AuthorConfig mixup

Created by: fred-wang

Followup of issue #556 (closed) :

if (window.MathJax) { window.MathJax = {AuthorConfig: window.MathJax} } else {window.MathJax = {}}

// MathJax.isPacked = true;

if(document.getElementById&&document.childNodes&&document.createElement){
  ...
    Normal MathJax.js code
  ...
}

then the packer will just add a comment header (no additional code) and uncomment the MathJax.isPacked = true line. And someone reading the unpacked code will directly see the logic of the packed version.