Deferred cancellers not getting called w/ XHR timeout

[jameyg]

xhr "timeout" calls Deferred.cancel() after Deferred.errback() which prevents cancellers from being called since the deferred is "finished".

In io.script, this also prevents the script tag from being removed from the DOM.

[jameyg]

Please reject this ticket...i got lost in the inflight check and misread a sequence.

[Kenneth G. Franqueiro]

Closing as requested.