Version 0.5

0.5

• Allow transformers-0.6, see #47.
• Drop dependencies on mtl and tasty. See #45, #46.
• Derive the stock Eq and Ord instances for Validation, see #43.
• Add selectT, see #42.
• Add more general instances for IdentityT and ReaderT. This is technically
  a breaking change because Selective is not a superclass of Monad. See #38.