abort to reconnect if isWrongStatusCodeOrContentType is true

Hi.

I found that this polyfill may not in accordance with the terms of the reconnection written [here][link1].

Although it's a very simple implements, I think it meets requirements.

Please review it and tell me your impressions.

I really thank you for creating such a useful polyfill. Thank you.


[link1]: http://www.w3.org/TR/eventsource/#processing-model "w3c"