Store Account IDs instead of Steam IDs

[alongubkin]

Steam IDs are different in the Source 2009 engine and the new P2/CSGO engine. We must store account ids instead of steam ids to offer Counter-Strike: Global Offensive support.

GetAccountIDFromAuthString(String:authString[])
{
    decl String:toks[3][16];

    ExplodeString(authString, ":", toks, sizeof(toks), sizeof(toks[]));

    new odd = StringToInt(toks[1]);
    new halfAID = StringToInt(toks[2]);

    return (halfAID*2) + odd;
}

(source: itemlogger)