Merge remote-tracking branch 'origin/session_management' into PeerAssessmentAxel

# Conflicts:
#	gemeinsamforschen/src/main/java/unipotsdam/gf/core/management/ManagementImpl.java
#	gemeinsamforschen/src/main/java/unipotsdam/gf/interfaces/IPeerAssessment.java
#	gemeinsamforschen/src/main/java/unipotsdam/gf/modules/assessment/controller/service/FBAssessement.java
#	gemeinsamforschen/src/main/java/unipotsdam/gf/modules/assessment/controller/service/PeerAssessment.java
#	gemeinsamforschen/src/main/java/unipotsdam/gf/modules/assessment/controller/service/PeerAssessmentDummy.java
#	gemeinsamforschen/src/main/webapp/core/pages/gemeinsamForschen.tld
#	gemeinsamforschen/src/scripts/dbschema/fltrail.sql