Implemented c_monoid<std::future<T>> allowing "a <PLUS> b" for two futures "std::future<T> a, b".
Implemented c_monoid<std::future<T>> allowing "a <PLUS> b" for two futures "std::future<T> a, b".

julian-becker/functional-templates,julian-becker/functional-templates,julian-becker/functional-templates,julian-becker/functional-templates