Handle hit chance and damage calculation

Math is based on what the UESP describes, with some tweaks (using
fatigue term, and the fCombatCriticalStrikeMult GMST):
http://www.uesp.net/wiki/Morrowind:Combat
Try to figure out what gets hit

This isn't the greatest. The distance multiplier is a guess, and a sphere cast
may be better.
Fix hit chance calculation