Use promises in place of callbacks for Client#send. Not working properly yet. refs #11
Re-fasctored promise implementation. Once-only implementation is working, need to enable persistent handlers
Promises chained together for persistent handlers. Performance is a problem, so will replace with a hybrid promise-callback approach
Re-factor to use combination of persistent callbacks and promises. Add ability to cancel callbacks and promises
Provide one-time callback behavior by callback return value instead of using Promises. Modify API annotations accordingly. Refs #11
Use delete operation for unregistering callback. Return true if callback was present, false otherwise. refs #11
Merge pull request #33 from ozone-development/feature-promise

Feature promise