LibClassicDurations Tracks all whitelisted aura applications and then returns UnitAura-friendly _duration, expirationTime_ pair
Benefits of installing this standalone package:
1) it's the first to get updates
2) You won't lose buff data after relogs
See https://github.com/rgd87/LibClassicDurations for usage example
In reply to mushies_:
It's bugged and won't refresh after 5 stacks