Wraps

Features

- Implemented `Either[L, R]` type.

Features

- Renamed `convert_optional -> wrap_optional`, added `extract` method.
This allows users to defer back to `Optional[T]`, along with wrapping
`Optional[T]` into `Option[T]` in a clear and concise way.
([1](https://github.com/nekitdev/wraps/pull/1))

Initial release.