Change healing logic

[MatthiasMoore]

The player will be healed when they are not full hp during boss battles.

Resolves #177

[meepen]

Correct me if im wrong - but the healing attack heals everyone, not just you, correct?

[MatthiasMoore]

Yea, the healing skill does heal others, and it seems the boss will randomly damage one of the ten players with its laser attack. It would be more efficient to check all players health values, and then apply it in an optimal way, but I was not thinking about that at the time.

[MatthiasMoore]

The new commits should now prefer healing when half the allies are not full hp. I will not have time to test it for a few hours, but looking over the logic a few times, it should function properly unless I am overlooking something simple.