- promisify
- merge health check for single node and cluster
- replace the first multi with simple SET in health check
- reworked health check with o-error context/stack-traces for failures
- drop console.error on health check timeout, consumer logs the error
- cleanup unwrapping of ioredis multi result
- Promise support for multi.exec
This has been squashed from das7pad s fork.
REF: b3dd8c5cf4cc6482fd450e6bb67013508844f93f