Add group system

Initial commit, not tested in multiplayer yet. Some revisions still left
to do.

SQF/dayz_code/groups/server_updateGroup.sqf

@@ -0,0 +1,42 @@
+private ["_event","_groupUIDs","_key","_newGroup","_player","_playerUID","_targetUID"];
+
+_event = _this select 0;
+_player = _this select 1;
+_targetUID = if (count _this > 2) then {_this select 2} else {"0"};
+_playerUID = getPlayerUID _player;
+
+_groupUIDs = [];
+{
+	if (alive _x && isPlayer _x) then {
+		_groupUIDs set [count _groupUIDs,getPlayerUID _x];
+	};
+} count (units group _player);
+
+_newGroup = [];
+_newGroup = switch _event do {
+	//Login
+	case 0;
+	//Join
+	case 1;
+	//Kick (target was already kicked from group)
+	case 2: {_groupUIDs};
+	//Leave
+	case 3: {
+		dayz_groupLeft = true;
+		(owner _player) publicVariableClient "dayz_groupLeft";
+		(_groupUIDs - [_playerUID])
+	};
+	//Disband
+	case 4: {
+		dayz_groupDisbanded = true;
+		(owner _player) publicVariableClient "dayz_groupDisbanded";
+		[]
+	};
+};
+
+// Update all group members' saved group in DB
+{
+	_save = if ((_event == 2 && _x == _targetUID) or (_event == 3 && _x == _playerUID)) then {[]} else {_newGroup};
+	_key = format ["CHILD:204:%1:%2:%3:",_x,dayZ_instance,_save];
+	_key call server_hiveWrite;
+} count _groupUIDs;