Unpack should return interface{} instead of reflect.Value

[smw1218]

I am trying to use this and the RPC library and I think the code requires a major refactor to match standard encoding libraries in Go. I have made changes on the ngmoco fork but I didn't want to open a pull request until there was some discussion around the matter.

I personally suggest trashing the current interface since this separate project is fairly new. It only took me a few hours to switch the code to something that is far more usable.