Animal graphics update — Afterworld Steam update #509553

Small update for the graphics of the animals, mostly for their walking sprite animation. Nothing too much, just defining them a little bet more so they all match closer in quality, and to make them a little less cartoony. The bird is given the biggest update. It is the only one with a major update to it's battle sprite. It looks much more realistic. I hope everyone enjoys this update, even if it is a small one.