- Push messaging - stack monitor folder logic
https://github.com/openpeer/opios-production/issues/93

- Push messaging - stack push mailbox login sequence
https://github.com/openpeer/opios-production/issues/35

- Push messaging - stack recheck now logic
https://github.com/openpeer/opios-production/issues/86

- Push messaging - stack "step" mechanism
https://github.com/openpeer/opios-production/issues/57

- Push messaging - stack push registration process handling
https://github.com/openpeer/opios-production/issues/52

- Push messaging - stack expose re-fetch API mechanism
https://github.com/openpeer/opios-production/issues/33

- fix: subscription notification of current state needs a strong reference