REFACTORED - Javadoc added and code/stability improvements.

Signed-off-by: Michael Grammling <m.grammling@external.telekom.de>
ADDED JUnit test case for the AbstractEventSubscriber.

Signed-off-by: Michael Grammling <m.grammling@external.telekom.de>
Update EventType.java
Merge pull request #14 from qivicon/stabilityimprovements-fixed

Stabilityimprovements fixed - CQ #8121