Remove ajaxSetup

Fixes #204

Turns out that we can't put withCredentials into ajaxSetup because of this internal jQuery code:
```js
	_evalUrl: function( url ) {
		return jQuery.ajax({
			url: url,
			type: "GET",
			dataType: "script",
			async: false,
			global: false,
			"throws": true
		});
	}
```