AFNetworking/AFNetworking — pull request #224 by kcharwood (2012-02-29 17:53:11+00:00)
Title: Added in cancel changes based on @zdzisiekpu's recommendation

I implemented @zdzisiekpu's recommendation in #212.

In `AFURLConnectionOperation`, I updated the `connection` property to be retained, and set the `connection` to nil in `connectionDidFinishLoading:`, `connnection:didFailWithError:`, and `cancelConnection`. This appears to solve my crash, but I am not sure if this a complete solution, or if flipping the property to retain opens up other unknown issues from some hidden retain cycle somewhere.