Log Message:
Update to 0.4.2.0

changelog:
0.4.2.0 Ross Paterson <ross@soi.city.ac.uk> Nov 2014
    * Dropped compatibility with base-1.x
    * Data.Functor.Identity in base for GHC >= 7.10
    * Added mapLift and runErrors to Control.Applicative.Lift
    * Added AutoDeriveTypeable for GHC >= 7.10
    * Expanded messages from mfix on ExceptT and MaybeT