Acid Damage Fix

Redid a portion of how pacid damage is calculated. People were not being disfigured when sprayed, and contact with acid for some reason had a 15% chance to do ridiculous damage (~30 per spray puff), otherwise it did very little (~6).

Disfigurement should be back, and damage should be more consistent around the ~12 range per spray puff. Sacid damage is the same, just halved.

Additionally:
-Pacid has a higher chance of melting things than sacid
-Headgear is melted before masks
-Glasses melt, too
-update_hair(0) is called when your equipment is melted so you don't appear bald and clean-shaven.
-Updated messages to use span