Changes with CS2

[Taraman17]

It shows, that in the CS2 Dedicated server, the behaviour of rcon answers is different than in CS:GO

1. On authentication, only one packet is sent as answer and the first empty packet is not there anymore.
2. There are no multipacket responses anymore - all answers are sent as single packet.

So it will be necessary to do some changes and it must be discussed, if that is done as if condition within this library or if it is better to fork it.