Bind instance for scala.Map
Bind instance for scalaz.==>>

https://github.com/ekmett/semigroupoids/blob/v4.0/src/Data/Functor/Bind.hs#L472-L474
add test for `scalaz.==>>`
add test for `scala.Map`
Merge pull request #584 from xuwei-k/map-bind

add Map Bind instance