Cheering as is done now is highly unfair and illogical. Cheering units are immune to all damage for 2.8 seconds.
That means unit A attacking cheering unit B is wasting its attack and doing 0 damage while taking damage from anyone attacking it (unit A).
That can save cheering unit with 1 HP from being killed what is not fair to the attacker.
In this diff I am:
1) removing immunity to damage while cheering
2) do not forcing cheering order so unit can respond to attacks
3) ignoring cheering order, unless unit is idle