remove dead code
use patched reactivemongo
hr "hrvatski" translation #1899. Author: Goran. changelog: some translations changed from Serbian to Croatian
Merge branch 'stable' of github.com:ornicar/lila

* 'stable' of github.com:ornicar/lila:
  hr "hrvatski" translation #1899. Author: Goran. changelog: some translations changed from Serbian to Croatian
simplify datetime display
fix user average elo counter using mongodb aggregation