Make promise.finally propagate unhandled rejection state

Fix #357
Prevent extra unhandled rejection report in when.all

See #356
Fix when.all case where same rejection appears twice
Propagate rejection jit in finally to avoid extra unhandled rejection
Verify actual rejection value in addition to count
Merge pull request #358 from cujojs/fix-unhandled-rejection-edge-cases

Fix unhandled rejection edge cases