Dicussion on encoding interface changes

[cjhubert]

Hey guys, I have some ideas that I wanted to discuss before doing any work in regards to encoding.

I think encoding should have an interface, similar to how the backend is already set up, allowing more encoding types.

Then, instead of separating the config manager into the two different standard and encoded types, it'd be a single one that would contain the backend and the encoder. If the encoder was nil, it would just add it to the store without any encoding. If it was not nil, it would call .Encode() on it and add it. Unfortunately, this would break backwards compatibility, but I think is an overall win in simplicity.

In the future, I'd like to add using the AWS Key Management Service as an encoding type (using AES from the GenerateDataKey() call). KMS would need to be added to goamz first, or we could make our own implementation here and just use a normal httpclient.

Let me know your thoughts on the matter, thanks!

[bketelsen]

I think this sounds reasonable. We can and should keep the old methods around for a while with doc comments warning that they're going to go away. OK?