Drop Monad constraint on mapNPM and friends about generics-mrsop

[VictorCMiraldo]

Pardon the delay in answering this.

I disagree purely out of stuborness: Applicative should not be a subclass of Monad and therefore,
I stick with Monad.

The reason is that a given monad always gives rise to TWO applicatives:

apL :: (Monad m) => m (a -> b) -> m a -> m b
apL mf ma = do
  f <- mf
  a <- ma
  return (f a)

apR :: (Monad m) => m (a -> b) -> m a -> m b
apR mf ma = do
  a <- ma
  f <- mf
  return (f a)

These two are only equal when the monad is strong.