Add group system

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

SQF/dayz_code/groups/promotePlayer.sqf

@@ -0,0 +1,23 @@
+private ["_disbandButton","_display","_group","_myGroup","_target","_uid"];
+
+disableSerialization;
+_display = findDisplay 80000;
+_myGroup = _display displayCtrl 2;
+_disbandButton = _display displayCtrl 5;
+_promoteButton = _this;
+_uid = _myGroup lbData (lbCurSel _myGroup);
+
+_group = group player;
+_target = _uid call dayz_getPlayer;
+
+if (player == leader _group && {!isNull _target} && {_target != player}) then {
+	if (local _group) then {
+		_group selectLeader _target; //group must be local
+		_promoteButton ctrlShow false;
+		_disbandButton ctrlShow false;
+	} else {
+		systemChat "Failed: Group must be local to do this";
+	};
+} else {
+	_promoteButton ctrlShow false;
+};