mtl-2.3.1: Monad classes for transformers, using functional dependencies

# mtl-2.3.1: Monad classes for transformers, using functional dependencies

MTL is a collection of monad classes, extending the `transformers` package, using functional dependencies for generic lifting of monadic actions.

Modules

- Control
  Submodules
  - Monad
    Submodules
    - Control.Monad.Accum
    - Control.Monad.Cont
      Submodules
      - Control.Monad.Cont.Class
    - Error
      Submodules
      - Control.Monad.Error.Class
    - Control.Monad.Except
    - Control.Monad.Identity
    - Control.Monad.RWS
      Submodules
      - Control.Monad.RWS.CPS
      - Control.Monad.RWS.Class
      - Control.Monad.RWS.Lazy
      - Control.Monad.RWS.Strict
    - Control.Monad.Reader
      Submodules
      - Control.Monad.Reader.Class
    - Control.Monad.Select
    - Control.Monad.State
      Submodules
      - Control.Monad.State.Class
      - Control.Monad.State.Lazy
      - Control.Monad.State.Strict
    - Control.Monad.Trans
    - Control.Monad.Writer
      Submodules
      - Control.Monad.Writer.CPS
      - Control.Monad.Writer.Class
      - Control.Monad.Writer.Lazy
      - Control.Monad.Writer.Strict