uivalent of 'concatMap'.
cMapM :: (Monad m) => (a -> m [b]) -> [a] -> m [b]
cMapM f xs = concat `liftM` mapM f xs

cMapM :: (Monad m) => (a -> m [b]) -> [a] -> m [b]
cMapM f xs = concat `liftM` mapM f xs
cMapM f xs = concat `liftM` mapM f xs