Features:
+* expose the handoff timestamp fully via the D-Bus properties that contain
+ ExecStatus information
+
+* properly serialize the ExecStatus data from all ExecCommand objects
+ associated with services, sockets, mounts and swaps. Currently, the data is
+ flushed out on reload, which is quite a limitation.
+
* Clean up "reboot argument" handling, i.e. set it through some IPC service
instead of directly via /run/, so that it can be sensible set remotely.