type class Optional[F[_]]

- abstracts over containers/contexts which may provide a value or not

- instances:
  - scala.Option
  - scalaz.LazyOption

- provides syntax.OptionalOps

- tests for all the functionality

I also have an instance for `scala.util.Try` but since cross compiling includes 2.9.2 I left it out.

I'm interested in what other instances you would support and what ideas you have for integration into the rest of scalaz.


BTW: The idea from this pull request started in the scalaz mailing list: https://groups.google.com/forum/#!topic/scalaz/4kH4jcp4z8E