Bugfix during closing a server.
Implement latency compensation during sending channel messages.
Set server datetime as channel log's created/last_updated values.
Sync client and server time.
Save user channel logs with server synced timestamp.
Mark channel message as sent once received by app server.
Optimize channelNamesListener.

We don't need to listen to channel's names list for each user joining
the same channel. Listening to this event for the first channel join will
suffice. Later, nicks joining and leaving channel are tracked by the
channel 'join' and 'part' events.
Merge branch 'master' of https://github.com/waartaa/waartaa