Rest-types: add instances for Functor/Foldable/Traversable.
rest-core/rest-types: add CHANGELOG entries.
Revert "Merge pull request #51 from mbrock/q"

We don't want to release this yet, since it's incompatible with
existing use of client libraries.

This reverts commit ae7f054ad1ccfcfc445f0b969539e72aa576e2da, reversing
changes made to 2e554f7b774569a6f5705e451b4755465ce6eb10.
Bump rest-core and rest-types.