Various damaged states for mob sprites

[cdsupina]

We should create damaged states for all of the mobs, especially the boss, so that as you do more damage, the texture changes.

We would probably want 3 states of damage total, one that looks normal for near full health (which we already have), one for a little damaged, and one for very damaged.

These should all be added to one sprite sheet along with the existing "normal" state for mobs and any future states that require an adjusted texture.