* properly handle .mount unit state tracking when two mount points are stacked one on top of another on the exact same mount point.
Features:
+
+* place start-pre/start-post/... scripts in sub cgrouprs
+
+* Make RuntimeWatchdogUSec= property writable
+
* start polkit agent in systemctl, similar to the password agent, to allow
gaining authorizations for privileged operations by entering a password:
Interface:
* add option to sockets to avoid activation. Instead just drop packets/connections, see http://cyberelk.net/tim/2012/02/15/portreserve-systemd-solution/
-* isolate for getty is still broken, due to logind
-
* default unix qlen is too small (10). bump sysctl? add sockopt?
* support units generated by a generator and placed in /run/systemd/system/; the directory is