2.0.0
Ver 2.0.0 improves Swift's type-inference by adding success() method
to reduce too many overloads on then() method.
task.progress()'sprogressClosuretype changed fromProgress -> Voidto(oldProgress: Progress?, newProgress: Progress) -> Voidtask.then(fulfilledClosure)is renamed totask.success()task.catch(catchClosure)is renamed totask.failure()task.then()is no longer used for fulfilled-only handling
See #8 for more information.