GH-850 Enable triggering of builds on `master` branch when it changes (#857)
GH-850 Enable triggering of builds on `master` branch when it changes (#857)

* add Jenkins file for master build

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