Features:
+* .timer units should optionally support CLOCK_BOOTTIME in addition to CLOCK_MONOTONIC
+
+* rm_rf() should be able to remove subvolumes
+
+* systemd-run should support a mode where we wait for the unit to be started up
+
* create a btrfs qgroup for /var/lib/machines, and add all container
subvolumes we create to it.
- add functions to set previously stored IPv6 addresses on startup and get
them at shutdown; store them in client->ia_na
- write more test cases
- - implement and do duplicate address detection, see rfc 4862, 5.4.
- implement reconfigure support, see 5.3., 15.11. and 22.20.
- implement support for temporary adressess (IA_TA)
- implement dhcpv6 authentication