Add group system

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

SQF/dayz_code/groups/groupInvite.sqf

@@ -0,0 +1,36 @@
+private ["_add","_inviter","_recipient","_uid","_unit"];
+
+_add = _this select 0;
+_uid = _this select 1;
+
+// Update active invites on all machines with the change
+if (_add) then {
+	_inviter = _uid select 0;
+	_recipient = _uid select 1;
+	dayz_activeInvites set [count dayz_activeInvites,_uid];
+	if (!isDedicated && {_recipient == getPlayerUID player} && {!dayz_requireRadio or {dayz_requireRadio && "ItemRadio" in items player}}) then {
+		localize "STR_EPOCH_INVITE_NEW" call dayz_rollingMessages;
+	};
+} else {
+	// Remove all invites to this player
+	_inviter = "0";
+	_recipient = _uid;
+	{
+		if (_recipient == _x select 1) then {
+			dayz_activeInvites set [_forEachIndex,"delete"];
+		};
+	} forEach dayz_activeInvites;
+	dayz_activeInvites = dayz_activeInvites - ["delete"];
+};
+
+// Send change to all active clients except the originator (they already updated themself)
+if (isServer) then {
+	PVDZ_groupInvite = _this;
+	{
+		_unit = getPlayerUID _x;
+		if (_unit != "" && ((!_add && _unit != _recipient) or (_add && _unit != _inviter))) then {
+			// Don't use regular PV because JIP clients don't need it (dayz_activeInvites is synced to them in server_playerLogin)
+			owner _x publicVariableClient "PVDZ_groupInvite";
+		};
+	} count allUnits;
+};