Add `take`/`drop`/`splitAt` to `Data.Map`/`Data.Set`

[Herbert Valerio Riedel]

On 2016-03-08 at 01:26:12 +0100, Dan Burton wrote:
> I would prefer that the Ord constraint be retained in the type signature,
> even if not used in the implementation.

Just for the record: You'll have to actively suppress the resulting
warning if the Ord dictionary is not used by the implementation, as
-Wredundant-constraints is part of -Wall starting with GHC 8.0

-- hvr