Merge remote-tracking branch 'tgaengler/master'
Merge remote-tracking branch 'slub/master'
Merge remote-tracking branch 'slub/master'
[TASK][DD-734] custom toString-methods for easier debugging
Merge remote-tracking branch 'slub/master' (and resolving conflicts
between two new simultaneously added constructors
 in src/main/java/org/dswarm/graph/json/ResourceNode.java)
Merge branch 'master' into githubmaster