v1
This release includes a few large API breaking changes:
* `Choice` is now called `Select`
* the `Prompt` interface is now based on `interface{}`s instead of `string`s
* `Validator` signature changed from `string -> error` to `interface{} -> error`
* Ask and AskOne now take a pointer to a value (similar to `json.Unmarshal`) instead of returning a `map[string] string`
* `AskOneValidate` was removed and instead a validator can be specified via the third argument added to `AskOne`