timesyncd: log drift correction
TODO
sd-rtnl: route - allow setting multiple matching routes
sd-rtnl-message: append - fix uninitialized memory

We were not properly clearing the padding at the front of some containers.
timesyncd: log drift value as signed
hwdb: update
core: require cgroups filesystem to be available

We should no longer pretend that we can run in any sensible way
without the kernel supporting us with cgroups functionality.
build-sys: move async.[ch] to src/shared

So that we can use it at multiple places.
update TODO
build-sys: enable timesyncd by default
timesync: always initialize structs when declaring them as far as possible with contsant values
timesync: use safe_close() where possible
sd-event: make it easy to bind signal handling to event loop exits

By passing a NULL callback provide a simple way to make event loops exit
on SIGTERM and other signals.
sd-event: allow disabling event sources when an event object is dying anyway
sd-resolve: make sure we can destroy a query object from its own callback handler
timesyncd: lookup name server via sd-resolve, support IPv6, react to SIGINT/SITERM
timesyncd: properly handle multiple configured NTP servers and multiplei IP addresses per server name
timesyncd: don't busy loop when we cannot connect to any servers
timesyncd: also try next server when sendto() fails
timesyncd: add a more servers by default