Add side-effect to BenachrichtigeReferentenBeiKonferenzAenderung

Allows for better automated testing.
Use rule as a more elegant approach to fixed datetime tests
Merge branch '2-jpa-classpathscan' into 3-jpa-custom-classpathscan
Merge branch '3-jpa-custom-classpathscan' into 5-javaconfig

Conflicts:
	de.andrena.et14.spring.konferenz/src/main/java/de/andrena/et14/spring/konferenz/KonferenzEntity.java
	de.andrena.et14.spring.konferenz/src/main/resources/META-INF/spring-konferenz-service-config.xml
	de.andrena.et14.spring.parent/pom.xml
	de.andrena.et14.spring.vortrag/src/test/java/de/andrena/et14/spring/vortrag/VortragDaoTest.java
Slightly update TODO in KonferenzServiceSpringConfig