Added support for linebreaks in equations

Now supports multiline equations:

MathJax.Hub.Config({
    'HTML-CSS': {
        linebreaks: {
            automatic: true
        }
        undefinedFamily: 'Amiri'
    }
});

To use this version update the configs like the following:

MathJax.Ajax.config.path["arabic"] = "https://cdn.rawgit.com/OmarIthawi/arabic-mathjax/v1.2/dist";

Try out the responsive demo: