New, better fix for BMK-247 (undo and replace the previous fix)

New, better fix for BMK-247 (undo and replace the previous fix). Use the "wait" command only to wait for all processes to complete, either succesfully or failing: wait for all processes together, do not check for individual exit codes via wait, and ignore the sderr/stdout of wait by piping it to /dev/null. Check the exit codes of individual processes by using the doOneWrapper logfiles.