Some cleanup based on Intellij code analysis.
Merge branch 'master' of github.com:DM2E/dm2e-ws

Conflicts:
	src/main/java/eu/dm2e/ws/api/AbstractPersistentPojo.java
	src/main/java/eu/dm2e/ws/services/AbstractRDFService.java
	src/main/java/eu/dm2e/ws/services/job/JobService.java
	src/test/java/eu/dm2e/ws/services/file/FileServiceITCase.java