[CHANGES]
- API changes to make duck-typing closer to Promises/A+ et.al:
- Allow sequencing methods to yield non-Future results; upgrade
them to being Future-wrapped
- Add ->resolve and ->reject as aliases of ->done and ->fail
- Allow sequencing methods to yield non-Future results; upgrade
- Recognise PERL_FUTURE_STRICT environment variable to restore
previous sequencing method behaviour
[BUGFIXES]
- ->without_cancel still needs to cancel result if caller is
cancelled
- Ensure all Future::AsyncAwait interop methods properly respect
subclassing