[Merge] lp:~phablet-team/history-service/optimize_dbus_traffic into lp:history-service/staging

[Tiago Salem Herrmann]

Review: Needs Fixing

Code looks good, but would be good to remove the qDebug()'s as they are getting triggered on every eventsAdded, modified and so on.
-- 
https://code.launchpad.net/~phablet-team/history-service/optimize_dbus_traffic/+merge/317649
Your team Ubuntu Phablet Team is subscribed to branch lp:~phablet-team/history-service/sort_by_multiple_fields.