[mr2984] Use Sql Statements in groups code and small code style
[mr2985] Group: extends requests about member role
[mr2986] Group: auto change group leader for suitable group member when leader gone

Fix situations, when raid in dungeon, set master loot, and leader gone for some reason.
Now after waiting to reconnecting leader, lead goes to another group member.
[mr2987] Mitigate DoS attacks to authserver

Mitigate DoS attacks to authserver like "Wow Auth Flooder.exe" by allowing a finite number of AUTH_LOGON_CHALLEGE packets in a row from same socket, 3 sounds like a reasonable limit.

Picked from TC, author jackpoz.
Merge branch 'master' of git://github.com/mangosR2/mangos