GH-533: Automatically start multibranch builds only for branch "master" (#534)
GH-533: Automatically start multibranch builds only for branch "master" (#534)

* disable all automatic builds except on branch "master"

* set build result to ABORTED

* roll back changes in Jenkinsfile.new

* add info message

lbeurerkellner/n4js,lbeurerkellner/n4js,lbeurerkellner/n4js,lbeurerkellner/n4js,lbeurerkellner/n4js