bump transformers dependency
version bump
Export Union data constructor
Merge pull request #12 from ibotty/master

bump transformers dependency
-Wall in test suite
https://github.com/RobotGymnast/extensible-effects/issues/14
Merge branch 'master' of github.com:RobotGymnast/extensible-effects

Conflicts:
	extensible-effects.cabal
Expose Union constructor: https://github.com/RobotGymnast/extensible-effects/issues/13.
Expose State constructors
Merge with upstream
Expose Reader constructor
Export Writer constructor