MessageDeliveryNotificationSource -> MessageSource
Conflicts:
	splitlog-core/src/main/java/com/github/triceo/splitlog/MessageListener.java
	splitlog-core/src/main/java/com/github/triceo/splitlog/NonStoringFollower.java
	splitlog-core/src/main/java/com/github/triceo/splitlog/NonStoringMergingFollower.java
MessageDeliveryCondition is no more
MessageDeliveryStatus.UNDECIDED