concrete functor and monad transformers

#68Lift's <*> is not lazy

The <*> implementation for Lift is not lazy in the sense that in order to get access to the contents of Other, the right operand of <*> must be in the WHNF.

This is easy to fix, e.g.:

instance (Applicative f) => Applicative (Lift f) where
    pure = Pure
    Pure f <*> ax = f <$> ax
    Other f <*> ax =
      Other $ f <*>
        (case ax of
          Pure x -> pure x
          Other y -> y

Please see for the motivation.