Features:
+* add an explicit parser for LimitNICE= and LimitRTPRIO= that verifies
+ the specified range and generates sane error messages for incorrect
+ specifications. Also, for LimitNICE= maybe introduce a syntax such
+ as "+5" or "-7" in order to make the limits more readable as they
+ are otherwise shifted by 20.
+
* do something about "/control" subcgroups in the unified cgroup hierarchy
* when we detect that there are waiting jobs but no running jobs, do something