Add getters for partition id and partition count in App class
Merge branch 'S4-102' into dev

Conflicts:
	subprojects/s4-core/src/main/java/org/apache/s4/core/App.java
	subprojects/s4-core/src/main/java/org/apache/s4/core/ReceiverImpl.java
	subprojects/s4-core/src/main/java/org/apache/s4/core/Sender.java
	subprojects/s4-core/src/test/java/org/apache/s4/fixtures/MockCoreModule.java