Loader.useXDomainRequest used to be enabled automatically for IE9 but is now always set to `false`. Please enable it only if you know your server set-up / CDN requires it, as some most certainly do, but we're finding them to be less and less used these days, so we feel it's safe to now disable this by default (#1248)

Loader.json was using the wrong context in IE9 with XDomainRequest calls (thanks @pnstickne #1258)