Rename methods of Monoid interface (unit instead of empty)
Refactor workflow composition
Provide monad composition for Option
Provide monad composition for List
Provide monad composition for Either
Provide monad composition for Id
Add SemiMonadComposition and SemiMonadInstances traits
Provide monad composition for Writer
Fix typo
Refactor (semi-)monads composition, introduce left- and right- composability interfaces.
Add spec for workflow compositions
Support composition of a pair of left- and right- composable (semi-)monads
Add monad composition for function[R] instance
Remove excessive type declarations
Derive monad from both idiom and semi-monad traits
Update Readme.md on workflow composition