Cabal revisions of free-3.4

Hackage metadata revisions edit the .cabal file after upload; each diff below is one revision.

 name:          free category:      Control, Monads version:       3.4+x-revision: 1 license:       BSD3 cabal-version: >= 1.10 license-file:  LICENSE     GADTs    build-depends:-    base                 >= 4       && < 5,+    base                 >= 4       && < 4.7,     bifunctors           >= 3,     distributive         >= 0.2.1,     transformers         >= 0.2.0   && < 0.4,