feat(really-core) : REALLY-64 TestCase for ObjectSubscriber and SubscriptionManager
REALLY-64 Fixed the SubscribeAggregator and implemented its test cases
Merge branch 'REALLY-64-Test' of github.com:HatemAlSum/really into REALLY-64

Conflicts:
	really-core/src/main/scala/io/really/gorilla/SubscriptionManager.scala