Update README.md
SubscriptionChildActor + tests
remove sbt parallel execution in tests
implement the subscription supervisor, class and tests
remove unstable assertions in tests
change the sleeping time in one test to be sure all the subscriptions are started
improve tests (for terminations)
improve tests (for terminations)
fix a stupid compilation error
remove within blocks (will be cause of errors)
improve code
merge with develop branch
improve code
fix a comment, move an import
remplace suid: String by suid: UUID
rename SubscriptionChild actors (with helper method)
standardise the All target name
fix bug in test suite (ALL -> all), change a method to a val
rename Subscription to Monitor
improve code in MonitorSuite