Add group system

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

SQF/dayz_code/system/scheduler/sched_oneachframe.sqf

@@ -28,6 +28,8 @@ sched_onEachFrame = {
 		hintSilent localize "str_player_lowPFS";
 		diag_log format [ "h1nt: LOW FPS (%1)", diag_fpsmin ];
 	};
+	
+	if (!isNil "dayz_groupIcons") then {call dayz_groupIcons;};
 
 	_ret
 };