Move initial enable/disable to End Extension hook, so that Asistive-Extension can adjust the SETTINGS beforehand (since Enable/Disable does that as well).  Also, move the ready signal to there as well, since we don't want to signal ready until after we endable/disable (though the menu can still cause a change).
Move initial enable/disable to End Extension hook, so that Asistive-Extension can adjust the SETTINGS beforehand (since Enable/Disable does that as well).  Also, move the ready signal to there as well, since we don't want to signal ready until after we endable/disable (though the menu can still cause a change).

mathjax/MathJax-RespEq,mathjax/MathJax-a11y,mathjax/MathJax-RespEq,mathjax/MathJax-a11y