[Proposal] Renaming (:=:) to (==)

As part of the discussion about Typeable, GHC 7.8 is going to include a Data.Type.Equality module that provides a polykinded type equality data type. I'd like to propose that we rename this type to (==) rather than the (:=:) it was developed under. We are already using (+), (-), (*), etc. at the type level in type-nats, so it would seem to fit the surrounding convention. I've done the work of preparing a patch, visible here: https://github.com/ekmett/packages-base/commit/fb47f8368ad3d40fdd79bdeec334c... Thoughts? Normally, I'd let this run the usual 2 week course, but we're getting down to the wire for 7.8's release. Once 7.8 ships, we'd basically be stuck with the current name forever. Discussion Period: 1 week -Edward Kmett