The Comonad type-class is the dual of Monad. Whereas Monads
allow for the composition of effectful functions, Comonads allow
for composition of functions that extract the value from their
The purpose of this type-class is to support the data-types in the
Monix library and it is considered a shim for a lawful type-class
to be supplied by libraries such as Cats or Scalaz or equivalent.
To implement it in instances, inherit from ComonadClass.
Credit should be given where it is due.The type-class encoding has
been copied from the Scado project and
Scalaz 8 and the type has
been extracted from Cats.