Change -1 to Null for GetManiastars..; Add GetOnlinePlayers.. for PlayersClient
Add GetFavo(u)ritedCount.. to ServersClient; Invert condition for Maniastars.
Add GetServerInfosAsync method.
Add method GetAllServerInfos

It automatically continues querying the API to feed the IEnumerable,
because: https://github.com/maniaplanet/maniaplanet-ws-sdk/issues/2