Updating the lib to be more consistent with other fantasy land repos

Update the tests to use fantasy-check …
- Removed the new keyword as we're using daggy and it's no longer required.
- Adding functor and monad test (should promise have ap, so we can test applicative functors?)

Adding ap promise. …
- Not entirely sure if ap is actually viable in this context, but it does seem to pass Applicative laws, which means either it does pass or the laws aren't well executed!?