add error handling for aborted requests for IE9

- when reading attributes from the XHR object from an aborted request in IE9 causes a breaking error. Namely  c00c023d.
- Added checks to see if the request has been aborted, and avoid reading the XHR attributes if it has.

Created a plunker to provoke the error:
http://plnkr.co/edit/PL86MNcE7Ljpll65c7pp?p=preview