Don't penalize XP for dodging

Currently, if you kill a monster and dodge every attack, you don't get
full XP. This changes that, so that taking damage OR dodging counts.

I noticed this because some kills I was only getting 1 point of XP, while
others I was getting 3. The kills where I dodged every attack (high defense)
only gained 1.

This still means a monster has to swing at you. Killing from safety does not get
good XP.