list events
Merge branch 'Siddhi-3.0.0' of https://github.com/sacjaya/siddhi into listEvents
support list events in callBacks
iterator
adding start and stop method to EternalReferencedHolder
adding StreamEventIterator
Merge branch 'listEvents' of https://github.com/sacjaya/siddhi into Siddhi-3.0.0
Merge branch 'listEvents' of https://github.com/sacjaya/siddhi into Siddhi-3.0.0