bumped required jenkins version to 1.480
added env var PROGRAM_DIR that contains the directory path of the current executable
working directory is set for each executable separately (so PROGRAM_DIR can be used to set a working directory relative to the current executable)
pattern to get the list of executable (include and exclude patterns) is not longer relative to the working directory (not sure, why it was implemented this way before, but thats clearly not the desired and expected behaviour)