XHR request failed, when appcache is used

[tujlaky]

If you use appcache, and make XHR requests to cached resources while offline, older webkit browsers finish the request with a statusCode of 0.

http://alistapart.com/article/application-cache-is-a-douchebag#section20

If I try to load a sprite's json file, I got error, because only response code 200 is allowed in this line: https://github.com/cykod/Quintus/blob/master/lib/quintus.js#L1757

I tested it with Android 2.3.7.