Upgrade promises-aplus-tests to 2.0
Deal with rogue thenables firing more than once
Resolve thenables returned inside other thenables
Catch errors from failing thenables
Only access the accessor once as required by Promises/A+ 1.1
Catch thenable accessor raising an Error
Handle special case of then call returning the promise itself as required by Promises/A+ 1.1
Don't reject a failing thenable if already fulfilled, and correcly bind thenable to this
Update docs