add requirement that Failed constructor and factory methods reject a passed TCE with an IAE.
Add requirement to throw IAE if TPE is passed to Failed constructor or factory method.
Changed withPayloads to infer and return the same type as the passed in function, and changed payload: Any parameter to => Any to be lazy.
Fixed withPayload not working in withFixture problem.
Fixed withClue not working in withFixture problem.
Rewritten withPayload and withClue to handle Failed and Canceled separately.
Added payload to TestCanceledException.
Added more tests for withPayload and withClue.