Doenst work with dataType XML

Hi,
thanks for this cool extension for `$.ajax` :)

But it doesnt work with `dataType: "xml"`
I get the following error:

`Uncaught Error: Syntax error, unrecognized expression: [object XMLDocument]`

Greetings

**Edit**
Does work if i use `dataType: "html"` and parse xml using `$.parseXML(respond)` afterwards
Maybe just add this to _Notes_ :)
