'giveup' needs args and kwargs of the function to be retried

[terrisgit]

I have a use case for a 'giveup' function to work conditionally, based on the arguments passed to the function to be retried.

[bgreen-litl]

The giveup function could take a details param like the event handlers. The downside is this would break the current contract and I don't think there's a good way to make it backward compatible. We could probably include this in backoff 2.0 though.